Stress-strain Relationship Determination Patents (Class 73/789)
  • Patent number: 6936471
    Abstract: An apparatus and method for screening combinatorial libraries of materials by measuring the response of individual library members to mechanical perturbations is described. The apparatus generally includes a sample holder for containing the library members, an array of probes for mechanically perturbing individual library members, and an array of sensors for measuring the response of each of the library members to the mechanical perturbations. Library members undergoing screening make up a sample array, and individual library members constitute elements of the sample array that are confined to specific locations on the sample holder. During screening, the apparatus mechanically perturbs individual library members by displacing the sample array (sample holder) and the array of probes. Typically, all of the elements of the sample array are perturbed simultaneously, but the apparatus also can also perturb individual or groups of sample array elements sequentially.
    Type: Grant
    Filed: February 8, 2001
    Date of Patent: August 30, 2005
    Assignee: Symyx Technologies, Inc.
    Inventors: Damian Hajduk, Eric Carlson, J. Christopher Freitag, Oleg Kolosov, James R. Engstrom, Adam Safir, Ravi Srinivasan, Leonid Matsiev
  • Patent number: 6901809
    Abstract: This need is met by the present invention wherein structural stress in a fatigue-prone region of a structure is determined by using the nodal forces and displacement values in the fatigue-prone region, or equilibrium-equivalent simple stress states consistent with elementary structural mechanics in the fatigue-prone region. The determination is substantially independent of mesh size and is particularly well-suited for applications where S-N curves are used in weld fatigue design and evaluation, where S represents nominal stress or stress range and N represents the number of cycles to failure. The present invention is directed to structural stress analysis through various combinations of modeling, calculation, and direct measurement schemes.
    Type: Grant
    Filed: November 16, 2001
    Date of Patent: June 7, 2005
    Assignee: Battelle Memorial Institute
    Inventors: Pingsha Dong, Jinmiao Zhang, Jeong Kyun Hong
  • Patent number: 6874369
    Abstract: A stress of a c-axis-oriented specimen of a tetragonal polycrystal is measured using X-ray diffraction under the assumption of a plane stress state. An X-ray optical system is set in the location of ?=0°, 45° or 90°. An X-ray diffracted at a crystal plane (the direction of the normal thereto is the direction of an angle of ?) with the Miller indices (hkl) is detected. A diffraction angle ? in a strain state is measured in the vicinity of a Bragg's angle ?0 in a non-strain state. Strains ? with respect to a plurality of ? are calculated from the difference between the measurement values ? and the Bragg's angle ?0. Specific stress calculation formulae are determined with respect to the tetragonal system having the Laue symmetry 4/mmm. The stress is calculated from the slope of the linear line of plotted measurement results.
    Type: Grant
    Filed: August 27, 2003
    Date of Patent: April 5, 2005
    Assignee: Rigaku Corporation
    Inventors: Ryouichi Yokoyama, Kamihisa Endo
  • Patent number: 6868735
    Abstract: Aged deterioration of ferromagnetic construction materials is nondestructively evaluated by applying to an evaluating material a magnetic field whose magnetic field amplitude is rather low, distinguishing various lattice defects, and quantifying them separately. A method includes obtaining a stress-strain relation in advance by a tensile test, evaluating a minor hysteresis loop (reference minor loop) while applying an applied stress (?) thereto, obtaining correlation between physical quantities for evaluating aged deterioration, obtaining a subject minor hysteresis loop (subject minor loop) by a tensile test, obtaining measured values of the physical quantities from the loop, and evaluating aged deterioration of the evaluating material from the measured values.
    Type: Grant
    Filed: October 7, 2003
    Date of Patent: March 22, 2005
    Assignee: Iwate University
    Inventor: Seiki Takahashi
  • Patent number: 6871162
    Abstract: A simple method of handling thermomechanical coupling for temperature computation in a rolling tire. First, the sensitivity of the tire elastic response to changes in material stiffness is characterized using the “deformation index”. Then, using a commercial finite element program and an appropriate user subroutine, heat generation is expressed as a function of the local temperature using a simple algebraic expression involving the temperature dependent material properties and the deformation indices. Temperatures are computed using the finite element program with the coupling information contained in the user subroutine. The result is a non-iterative method for a fully-coupled thermomechanical analysis of a tire. The effects of compound changes on tire temperature distribution can also be estimated using the deformation index. The method applies to the energy loss and temperature calculations under both steady-state and transient conditions.
    Type: Grant
    Filed: October 2, 2002
    Date of Patent: March 22, 2005
    Assignee: The Goodyear Tire & Rubber Company
    Inventors: Shingo Futamura, Arthur Allen Goldstein
  • Patent number: 6845671
    Abstract: A system and method is used for estimating the properties of a flexural beam. The beam is shaken transverse to its longitudinal axis. Seven frequency domain transfer functions of displacement are measured at spaced apart locations along the beam. The seven transfer functions are combined to yield closed form values of the flexural wavenumber in propagation coefficients at any test frequency.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: January 25, 2005
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Andrew J Hull
  • Patent number: 6829563
    Abstract: A simulation method of estimating performance of a product made of a viscoelastic material, comprising the steps of measuring a value of a strain, a strain speed, and a stress generated in viscoelastic material momently in a measuring condition equivalent to a state in which the product is actually used; deriving time history data of a viscosity resistance of the viscoelastic material separately in each of a strain increase state and a strain decrease state from time history data of the strain, the strain speed, and the stress and a viscoelastic model set in consideration of a viscosity of the viscoelastic material; setting the product as a product model whose performance is analyzed and inputting a relationship among the strain, the strain speed, and the viscosity resistance to the product model to conduct a simulation in consideration of a phenomenon that the viscosity resistance changes in dependence on a variation of the strain and the strain speed and in consideration of a difference in the viscosity res
    Type: Grant
    Filed: May 8, 2002
    Date of Patent: December 7, 2004
    Assignee: Sumitomo Rubber Industries, Ltd.
    Inventors: Kazuyoshi Miyamoto, Masahiko Ueda, Masaki Shiraishi
  • Patent number: 6826491
    Abstract: Method and apparatus for providing film stress measurements. The invention provides a method for calculating film stress based on an inverse finite element analysis of a displaced substrate such as a semiconductor wafer. The surface displacement of the substrate is measured, and structural compliance based on an inverse finite element model of the substrate is determined. A stress field is ultimately calculated based on the structural compliance and a stress-load. The stress measurement is output based on values in the stress field. The invention can be implemented in software running on a computer system interfaced to a measurement system such as a stress and flatness gauge.
    Type: Grant
    Filed: July 17, 2001
    Date of Patent: November 30, 2004
    Assignee: Wisconsin Alumni Research Foundation
    Inventor: Anton F. Jachim
  • Patent number: 6766697
    Abstract: A hydrodynamic bearing includes a fiber optic sensor for measuring static and dynamic bearing forces or loads during operation. The fiber optic sensor is positioned within the bearing through the most direct load path, which is through the pad support for a tilting pad style bearing. In additional to being positioned in the pad support of a tilting pad bearing, the sensor is also placed 1) inside the pad support or on the pad support structure, and 2) oriented perpendicularly with the shaft centerlines. After the sensor location is chosen and the sensor is properly positioned, a calibration procedure is utilized to determine the relationship between the radial load and measured strain for the specific bearing. Once the calibration factor has been determined, the sensor may be utilized in the bearing to measure load during operation.
    Type: Grant
    Filed: December 5, 2001
    Date of Patent: July 27, 2004
    Assignee: Bearings Plus, Inc.
    Inventors: Robert X. Perez, Natividad S. Ibanez
  • Publication number: 20040134285
    Abstract: A state information system for acquiring measured values of chemical and/or physical variables during the production, processing or finishing of a material, in particular in the case of a printing material web in a web-fed press, includes at least one sensor for recording the chemical and/or physical variables, the state information system being provided on or in the material such that the operating process carried out with the material remains unaffected by it.
    Type: Application
    Filed: December 3, 2003
    Publication date: July 15, 2004
    Applicant: MAN Roland Druckmaschinen AG
    Inventors: Johann Koniger, Werner Scherer, Andreas Birkenfeld
  • Publication number: 20040112140
    Abstract: Aged deterioration of ferromagnetic construction materials is nondestructively evaluated by applying to an evaluating material a magnetic field whose magnetic field amplitude is rather low, distinguishing various lattice defects, and quantifying them separately. A method includes obtaining a stress-strain relation in advance by a tensile test, evaluating a minor hysteresis loop (reference minor loop) while applying an applied stress (&sgr;) thereto, obtaining correlation between physical quantities for evaluating aged deterioration, obtaining a subject minor hysteresis loop (subject minor loop) by a tensile test, obtaining measured values of the physical quantities from the loop, and evaluating aged deterioration of the evaluating material from the measured values.
    Type: Application
    Filed: October 7, 2003
    Publication date: June 17, 2004
    Inventor: Seiki Takahashi
  • Patent number: 6718833
    Abstract: A multiaxial high cycle fatigue test system for testing bending, torsion, and tension of a test unit, comprises servo-hydraulic components, including a hydraulic service manifold, two small high frequency actuators along a first axis, and one large main actuator along a second axis The large main actuator is used to apply a radial centrifugal force, and the two small actuators are used to apply vibratory loading; the two small side actuators being offset independently of each other, to enable the machine to apply both bending loads and torque to the test unit. The test unit is subjected to torsion loading when the traverse actuators move in phase, that is when both actuators move either in or out at the same time. The test unit is subjected to bending loading when the actuators move out-of-phase, that is one actuator moves in when the other moves out or vice-versa.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: April 13, 2004
    Assignees: AdTech Systems Research, Inc., The United States of America as represented by the Secretary of the Air Force
    Inventors: Ming Xie, Som R. Soni, Charles J. Cross, Gary E. Terborg
  • Patent number: 6715364
    Abstract: In a method for determining the elasto-plastic behavior of components consisting of anisotropic material, in particular of gas turbine installations, at high temperatures, in which method, first of all, the linear-elastic behavior is determined and, on the basis of the linear-elastic results, the inelastic behavior is also taken into account by applying Neuber's rule, the anisotropic properties of the components, as occur in particular on account of the use of single crystal materials, are taken into account in a simple manner by using a modified anisotropic Neuber's rule of the form σ * 2 = σ ep 2 + σ ep 2 ⁢ D _ · E — —
    Type: Grant
    Filed: April 11, 2002
    Date of Patent: April 6, 2004
    Assignee: Alstom Technology Ltd
    Inventors: Otto Bernhardi, Roland Muecke
  • Patent number: 6694815
    Abstract: To predict residual settlement quantity and residual horizontal deformation quantity of ground where a liquefaction phenomenon has occurred due to earthquake. Soils in situ (stratum B to stratum D) are sampled from ground, and are made to be element test object stratums. A stratum whose characteristic is well-known, or the like may be substituted for a numerical model (stratum A). Next, setting of input conditions is performed, and vertical stress, horizontal stress and initial shear stress, which are equivalent to applied load that the ground at a depth of the point suffers, are worked on to each stratum. This recreates a stress status of soil before earthquake occurs. Then, shear displacement and the movement quantity of interstitial water by earthquake are given to the test piece, and the quantity of shear stress and pore water pressure, which have occurred, is obtained.
    Type: Grant
    Filed: March 13, 2003
    Date of Patent: February 24, 2004
    Assignee: Tohoku Techno Arch Co., Ltd.
    Inventors: Motoki Kazama, Noriaki Sentou, Akira Yamaguchi
  • Patent number: 6692983
    Abstract: A method of forming a color filter on a substrate having pixel driving elements. A substrate having a plurality of light-transmitting areas and active areas is provided. A pixel driving element is formed on the substrate in each active area, wherein an insulation layer is formed between each pixel driving element. A planarization layer is formed on the pixel driving elements and the insulation layer. Part of the planarization layer is removed to form contact holes and openings, wherein the contact holes expose part of the pixel driving elements, and the openings expose the insulation layer in the light-transmitting areas. Color pigment is filled into the openings to form a color filter on the substrate having the pixel driving elements. Transparent pixel electrodes are formed in the contact holes to electrically connect the pixel driving elements, wherein the transparent electrodes extend onto part of the color filter.
    Type: Grant
    Filed: March 26, 2003
    Date of Patent: February 17, 2004
    Inventors: Chih-Chiang Chen, Ching-Sang Chuang, Jiun-Jye Chang
  • Publication number: 20040025596
    Abstract: The invention relates to a force transducer, which is inserted into a small boring inside a test object and which, inside the boring, can measure the elastic extensions caused by the surrounding stress matrix. The force transducer is provided in two parts consisting of an outer part and of an inner part. Both parts are provided with a conical inner boring or conical outer periphery in such a manner that they can be held inside the boring of the test object by a tractive force generated using any means. In order to span a large tolerance zone the measuring boring, the outer part is axially provided with multiple slits on both sides. Said outer part is provided with a polygonal shape and thereby detects the deformations to be measured not over the entire periphery, but it records these via the contacts axially oriented through the angle lines. The extension is integrated in a peripheral direction between said contacts and is transferred into the inner part provided with any type of measuring device.
    Type: Application
    Filed: July 8, 2003
    Publication date: February 12, 2004
    Inventors: Falk Tegtmeier, Manfred Peters
  • Publication number: 20040011137
    Abstract: The present invention provides a system 10 for measuring and remotely monitoring strain in an element 1 having a strain sensor 20, a telemetry circuit 40 for transmitting strain data to a remote location, and a reader module 60 for transmitting energy to the telemetry circuit and receiving said data.
    Type: Application
    Filed: July 10, 2003
    Publication date: January 22, 2004
    Inventors: William P. Hnat, John F. Naber, Kevin M. Walsh
  • Patent number: 6662631
    Abstract: A method and apparatus for evaluation of films, such as low-k thin films with nano-scale pores, are provided. The evaluation may include characterization of the pore structure, the characterization results in determining pore sizes, hence obtaining pore size data. Moreover, the characterization may result in a non-destructive evaluation of mechanical properties, in particular the Young's Modulus, or the effect of interfering physical & chemical factors such as Pore Killers. Further, in line monitoring or studying of pore structure porosity and pore size distribution (PSD) of low-k films and evaluation of the mechanical properties of porous low-k films simultaneously using the same set of experimental data is provided.
    Type: Grant
    Filed: July 12, 2002
    Date of Patent: December 16, 2003
    Assignees: Interuniversitair Microelektronica Centrum, Technokom-Centre Advanced Technology, XPEQT
    Inventors: Mikhail Rodionovich Baklanov, Konstantin Petrovich Mogilnikov, Karen Maex, Denis Shamiryan, Fedor Nikolaevich Dultsev
  • Patent number: 6647802
    Abstract: A creep testing fixture and method for applying a precise amount of constant tensile stress to a creep test specimen to allow for precise measurement of creep in the test specimen. The fixture includes first and second mounting grips for holding opposite ends of a test specimen. A frame supports the mounting grips for relative reciprocal movement toward and away from each other. A tensile spring is connected between the first and second mounting grips. The frame subjects a test specimen held between the mounting grips to tensile stress in response to axially inward force that the tensile spring applies to the frame.
    Type: Grant
    Filed: March 29, 2001
    Date of Patent: November 18, 2003
    Assignee: Automotive Composites Consortium
    Inventors: Kelly Willson-Hackworth, Steven George Luckey, Jr., Daniel Q. Houston, Edward M. Hagerman, John M. Henshaw
  • Patent number: 6631647
    Abstract: A materials characterization method models dynamic, non-linear, temperature-dependent stress, strain, hysteresis, creep, and loss of elasticity at high strain, both in test samples and in Finite Element Analysis (FEA). Incorporating universal properties of statistical mechanics and adapting domain models from ferromagnetics to the higher-dimensional realm of stress tensors, the model is applicable to polymers, rubbers, liquids, and metals in elastic and plastic deformation. The model quantifies the dynamics of both plastic and brittle failure. Apparatus and methods are shown for testing material samples and matching the computational model to sample characteristics, leading to a set of characterizing parameters and predictive simulations using those parameters. Though apparatus and testing protocols of the invention yield optimum characterizations, pre-existing data from conventional testing yield useful results.
    Type: Grant
    Filed: April 26, 2002
    Date of Patent: October 14, 2003
    Inventor: Joseph B. Seale
  • Patent number: 6622567
    Abstract: A sensing device includes an RFID chip and a differential variable reluctance transducer (DVRT) sensor that can be read remotely with electromagnetic power provided to the device from a remote reader. The ac signal provided to the device by inductance is used for powering the RFID chip and exciting the sensor. Data read from the sensor can also be transmitted back to the reader using the power provided by the reader. The sensor circuit uses a lower amount of current than the RFID chip, so it does not contribute appreciably to device power requirements.
    Type: Grant
    Filed: March 7, 2001
    Date of Patent: September 23, 2003
    Assignee: Microstrain, Inc.
    Inventors: Michael John Hamel, Christopher Prvyn Townsend, Steven W. Arms
  • Patent number: 6609428
    Abstract: A method for estimating the real and imaginary Young's modulus, shear modulus and Poisson's ratio of a specimen at an excitation frequency. The specimen is first joined to a reciprocating test apparatus at one end with a mass positioned at the other end. The test apparatus reciprocates at the excitation frequency and accelerations are recorded at each end of the specimen. The Young's modulus is calculated from the recorded accelerations. The specimen is then joined to a reciprocating rotational test apparatus at one end with a rotational inertial mass positioned at the other end. Accelerations are recorded upon subjecting the specimen to rotational reciprocations at the excitation frequency. The shear modulus is calculated from these accelerations. Poisson's ration can be calculated from the Young's modulus and the shear modulus at the excitation frequency. All of the calculations may be performed giving both real and imaginary values.
    Type: Grant
    Filed: January 19, 2001
    Date of Patent: August 26, 2003
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Andrew J. Hull
  • Patent number: 6581473
    Abstract: A method for analyzing creep characteristic of a plastic molded substance is provided wherein the creep characteristic can be analyzed of an actual plastic molded substance having various shape and fastening conditions with high precision. The main stress value for each section of the analysis target is read out, hydrostatic stress &sgr;m of each section is calculated from the main stress value, and the stress condition is determined to be tensile stress when &sgr;m is positive and to be compressive stress when &sgr;m is negative. Tensile or compressive characteristic value is assigned based on the stress condition at each section, and creep is calculated for a predetermined time period based on the characteristic value. By employing characteristic values depending on the stress conditions of each section, precision of creep characteristic analysis is greatly enhanced.
    Type: Grant
    Filed: August 31, 2001
    Date of Patent: June 24, 2003
    Assignees: Toyota Jidosha Kabushiki Kaisha, Kanto Jidosha Kogyo Kabushiki Kaisha
    Inventors: Tadayoshi Takahara, Jun Chen, Yoshio Sugimoto
  • Patent number: 6564646
    Abstract: The invention relates to a method of measuring the biaxial shaping behaviour of metal materials, more particularly sheet metal. In the measuring method a flow locus curve comprehensively describing the shaping behaviour of the material is determined by determining the flow limits under tensile and compressive loading of secondary samples of a primary sample previously subjected to at least tensile, but preferably also to compressive loading. Preferably a number of flow locus curves of different preliminary loading of the primary sample are determined for each material. These flow locus curves, completely ascertained by tests, provide the further processor with a reliable ancillary means of selecting a material required for the particular shaping operation.
    Type: Grant
    Filed: January 4, 1999
    Date of Patent: May 20, 2003
    Assignee: Thyssen Stahl AG
    Inventors: Jörg Gerlach, Klaus Blümel
  • Publication number: 20030070491
    Abstract: A method for analyzing creep characteristic of a plastic molded substance is provided wherein the creep characteristic can be analyzed of an actual plastic molded substance having various shape and fastening conditions with high precision. The main stress value for each section of the analysis target is read out, hydrostatic stress &sgr;m of each section is calculated from the main stress value, and the stress condition is determined to be tensile stress when &sgr;m is positive and to be compressive stress when &sgr;m is negative. Tensile or compressive characteristic value is assigned based on the stress condition at each section, and creep is calculated for a predetermined time period based on the characteristic value. By employing characteristic values depending on the stress conditions of each section, precision of creep characteristic analysis is greatly enhanced.
    Type: Application
    Filed: August 31, 2001
    Publication date: April 17, 2003
    Inventors: Tadayoshi Takahara, Jun Chen, Yoshio Sugimoto
  • Patent number: 6539810
    Abstract: A method to estimate the tensile properties of HIPed cast IN718 components at various grain sizes and different operating temperatures by using transfer functions to estimate ultimate tensile strength, yield strength, and elongation.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: April 1, 2003
    Assignee: General Electric Company
    Inventor: Ling Yang
  • Publication number: 20020178832
    Abstract: The relationship between the stress &sgr; and the strain &egr; is firstly established in step 100 with short-term tests as a function of the temperature T. In steps 101 to 104, a Findley model is extended in such a way as to obtain a relationship between the strain &egr; and the stress &sgr; as a function of the time t and the temperature T. The two models are combined in steps 105 and 106, so as to obtain overall a relationship between the stress &sgr; and the strain &egr; as a function of the time t and the temperature T.
    Type: Application
    Filed: March 27, 2002
    Publication date: December 5, 2002
    Inventors: Bahman Sarabi, Martin Wanders, Dietmar Wachtler, Andreas Wende
  • Patent number: 6478753
    Abstract: The invention describes a device used to measure the tension of a soft tissue 24 attached to bones 20,22. The device 2 comprises a body region 4 having force applying hook shaft 6a and abutment spike shaft 8a extending outwardly therefrom. A spike region 8b of the abutment spike shaft 8a is extended in direction X to thereby abut the surface of bone 22. The force of the abutment is measurable by a displacement on a translation scale 14. An operator pulls on the device 2 in direction Y thereby applying an anterior force (measured by a displacement on a force scale 14) to the tissue 24 via a hook region 6b of the force applying hook shaft 6a. The application of said anterior force on to the tissue 24 results in an anterior translation of the tissue 24. The tension of the tissue 24 may be calculated from the displacements on the force scale 12 and translation scale 14.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: November 12, 2002
    Assignee: Atlantech House
    Inventor: Clive Reay-Young
  • Patent number: 6479170
    Abstract: The present invention provides an electrodeposited copper foil which solves problems of electrodeposited-copper-clad laminates to which the foil has been incorporated, such as bow, twist, and poor dimensional stability, and a method of inspecting an electrodeposited copper foil so as to assure the quality of the foil. In the invention, there is employed an electrodeposited copper foil which recrystallizes by heating at low temperature during production of a copper-clad laminate employing an electrodeposited copper foil and which exhibits an elongation as high as 18% or more in an atmosphere of 180° C., wherein the maximum rate of decrease in maximum tensile strength falls within the aging time ranging from 5 to 10 minutes in a process in which tensile strength decreases as time elapses during aging in an atmosphere at 170° C., and the change in tensile strength in a knick portion shown in a {tensile strength} vs.
    Type: Grant
    Filed: January 5, 2001
    Date of Patent: November 12, 2002
    Assignee: Mitsui Mining & Smelting Co., Ltd.
    Inventors: Naotomi Takahashi, Yutaka Hirasawa
  • Publication number: 20020157478
    Abstract: A materials characterization method models dynamic, non-linear, temperature-dependent stress, strain, hysteresis, creep, and loss of elasticity at high strain, both in test samples and in Finite Element Analysis (FEA). Incorporating universal properties of statistical mechanics and adapting domain models from ferromagnetics to the higher-dimensional realm of stress tensors, the model is applicable to polymers, rubbers, liquids, and metals in elastic and plastic deformation. The model quantifies the dynamics of both plastic and brittle failure. Apparatus and methods are shown for testing material samples and matching the computational model to sample characteristics, leading to a set of characterizing parameters and predictive simulations using those parameters. Though apparatus and testing protocols of the invention yield optimum characterizations, pre-existing data from conventional testing yield useful results.
    Type: Application
    Filed: April 26, 2002
    Publication date: October 31, 2002
    Inventor: Joseph B. Seale
  • Publication number: 20020129660
    Abstract: A method for estimating the real and imaginary Young's modulus, shear modulus and Poisson's ratio of a specimen at an excitation frequency. The specimen is first joined to a reciprocating test apparatus at one end with a mass positioned at the other end. The test apparatus reciprocates at the excitation frequency and accelerations are recorded at each end of the specimen. The Young's modulus is calculated from the recorded accelerations. The specimen is then joined to a reciprocating rotational test apparatus at one end with a rotational inertial mass positioned at the other end. Accelerations are recorded upon subjecting the specimen to rotational reciprocations at the excitation frequency. The shear modulus is calculated from these accelerations. Poisson's ration can be calculated from the Young's modulus and the shear modulus at the excitation frequency. All of the calculations may be performed giving both real and imaginary values.
    Type: Application
    Filed: January 19, 2001
    Publication date: September 19, 2002
    Inventor: Andrew J. Hull
  • Publication number: 20010049967
    Abstract: A method and apparatus for determining bulk material constants such as Poisson's ratio and the ratio of shear modulus to bulk modulus for elastomeric materials, including, but not limited to elastomers, rubbers, gels and sealants is disclosed. The bulk material properties are determined by measuring the pressure change of the elastomeric material when the elastomeric material is subjected to an applied pressure. The changes in the bulk material property due to temperature or a the addition of a diluent may also be determined. The apparatus includes a container that holds the elastomeric material. A pressure sensor is located in the container and is positioned to measure the pressure of the elastomeric material. The signal from the pressure sensor along with the applied pressure is used to determine a bulk material property such as Poisson's ratio or the ratio of shear modulus to bulk modulus for the elastomeric material.
    Type: Application
    Filed: April 3, 2001
    Publication date: December 13, 2001
    Inventors: David A. Dillard, Didier Lefebvre, Jang-Horng Yu
  • Patent number: 6311135
    Abstract: Provided are methods and apparatus for determining from indentation testing the preexisting stress and/or effective strain in a section of a material. The invention also provides methods and apparatus for determining the variation of the stress with depth in the material (e.g. the gradient). According to the invention, first data are provided from an indentation test of the stressed (or strained) section. The stress (or effective strain) can then be determined from the first data and from second data characteristic of the material, such as a stress-strain curve. Second data can also be obtained from an additional indentation test of a section having a known stress. The methods provided herein are suitable for programming on a general purpose computer or calculator.
    Type: Grant
    Filed: July 21, 2000
    Date of Patent: October 30, 2001
    Assignee: Inventium LLC
    Inventors: Subra Suresh, Antonios Giannakopoulos
  • Patent number: 6301970
    Abstract: A method of predicting fatigue failure in a filled polymeric material is provided. The method involves the calculation of stress at the region of highest stress using an equation which includes as parameters, regression coefficients of the stress vs. modulus obtained from a finite element analysis. Once the regression coefficients are obtained, there is no further need to perform a finite element analysis. The calculated stresses are numerically integrated in a damage equation using a Monte Carlo method, using a cumulative model to estimate when failure will occur. The method has been tested in the case of temperature stress loading of a solid propellant rocket motor.
    Type: Grant
    Filed: August 4, 1999
    Date of Patent: October 16, 2001
    Assignee: The United States of America the Secretary of the Navy
    Inventors: Gary L. Biggs, John J. Nestor, III
  • Patent number: 6267011
    Abstract: A small punch test apparatus is used to determine true stress and true strain in a ductile polymeric material as it undergoes deformation by the punch head. The information gathered can be used comparatively to assess the acceptability of a body implant subjected to sterilization against similar information obtained on another implant of the same polymer already known to be acceptable.
    Type: Grant
    Filed: March 31, 1999
    Date of Patent: July 31, 2001
    Assignee: Exponent, Inc.
    Inventors: Steven Michael Kurtz, Charles William Jewett, Jude Reynold Foulds
  • Patent number: 6155104
    Abstract: Provided are methods and apparatus for determining from indentation testing the preexisting stress and/or effective strain in a section of a material. The invention also provides methods and apparatus for determining the variation of the stress with depth in the material (e.g. the gradient). According to the invention, first data are provided from an indentation test of the stressed (or strained) section. The stress (or effective strain) can then be determined from the first data and from second data characteristic of the material, such as a stress-strain curve. Second data can also be obtained from an additional indentation test of a section having a known stress. The methods provided herein are suitable for programming on a general purpose computer or calculator.
    Type: Grant
    Filed: May 26, 1998
    Date of Patent: December 5, 2000
    Assignee: Subra Suresh
    Inventors: Subra Suresh, Antonios Giannakopoulos
  • Patent number: 6148675
    Abstract: Strain of an object is measured by a bridge having, in one arm thereof, a strain gage for producing a resistance change depending on the strain developed in the object, and having resistors in the respective remaining three arms thereof. The resistors have respective resistances independent of the strain developed in the object. A pair of power corners are disposed at one pair of diagonally opposite joints, and a pair of signal corners are disposed at another pair of diagonally opposite joints of the strain gage. Strain is measured by detecting an output voltage between the signal corners of the bridge as an initial unbalanced output voltage e.sub.0 while no strain is being detecting by the strain gage, applying a power supply voltage between the power corners of the bridge, and detecting an output voltage e between the signal corners to detect strain of the object. Strain developed in the object is measured based on a value .epsilon..sub.
    Type: Grant
    Filed: December 11, 1998
    Date of Patent: November 21, 2000
    Assignee: Tokyo Sokki Kenkyujo Co., Ltd.
    Inventor: Haruki Okano
  • Patent number: 6000277
    Abstract: A method of predicting rupture failure for corroded transmission pipelines uses a model that accounts for the effects of residual and thermal stresses, and settlement of the pipe following installation. The pressure required for failure under a fixed bending moment is different from the pressure required wherein the same bending moment is produced by the settlement of the pipe because the bending compliance increases with plastic straining. The failure criterion depends upon whether or not the hoop strain exceeds the difference between the ultimate hoop strain limit of the material and the remaining hoop strain capacity needed for the material to shed the axial stresses due to bending.
    Type: Grant
    Filed: June 5, 1998
    Date of Patent: December 14, 1999
    Assignee: Southwest Research Institute
    Inventors: Marina Quiocho Smith, Wei Wang, Carl Harry Popelar, James Alan Maple
  • Patent number: 5959215
    Abstract: The major object of this invention is to provide a heat build-up/fatigue measuring method for a viscoelastic body and a hydraulic servo flexometer, that enable direct measurement of a strain (displacement) and a stress (load) applied to a test piece and realize highly precise measurement by controlling the stress and the strain applied to the test piece by hydraulic servo feedback control based on the measured strain and stress.The hydraulic servo flexometer of this invention includes an upper anvil (22) and a lower anvil (18) having opposing parallel flat surfaces that form test piece holding surfaces, a hydraulic servo cylinder (19) having a piston rod (21) which is coupled to the upper anvil (22) or lower anvil (18) and which actuates in a direction perpendicular to the test piece holding surfaces, and a hydraulic servo mechanism for applying static and dynamic loads to the test piece (23).
    Type: Grant
    Filed: December 4, 1996
    Date of Patent: September 28, 1999
    Assignee: Bridgestone Corporation
    Inventors: Shigeki Ono, Chikahiro Satoh, Akira Yamada
  • Patent number: 5952647
    Abstract: A force-measuring apparatus is provided having a first plate, a second plate disposed above the first plate and spaced apart from the first plate, an optical sensor having at least one optical fiber disposed between the first plate and the second plate, and a clamp for moving the first plate and the second plate together to compress the optical fiber, thereby applying a prestressing force to the fiber to reduce eccentricity effects.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: September 14, 1999
    Assignee: SEB S.A.
    Inventors: Michel Sarrazin, Bernard Pitaud, Yves Patras, Benoit Linglin, Alain Duborper
  • Patent number: 5856621
    Abstract: An elastic modulus of an element of a material including fibers in a selected direction is determined as follows. First, a parallel elastic modulus, an orthogonal elastic modulus and fiber orientation of the material are stored. The elastic modulus of the element is determined based on the first elastic modulus, the second elastic modulus and an angle between the fiber orientation of the element and the selected direction such that the elastic modulus is determined as a function of the angle between the fiber orientation of the element and the selected direction when the selected direction is neither parallel nor orthogonal to the fiber orientation of the element.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: January 5, 1999
    Assignee: NECCorporation
    Inventor: Yohsuke Watanabe
  • Patent number: 5841040
    Abstract: A method of analyzing a structure containing a rigid body. The method defines a set of displacement factors to be imposed on a structure model. The method is used for calculating structure stress defining equations including a load vector representing externally applied forces on the structure model. The method modifies the load vector to compensate for rigid body deformation and evaluates stresses on the structure model from data generated from the structure stress defining equations.
    Type: Grant
    Filed: November 19, 1997
    Date of Patent: November 24, 1998
    Assignee: McDonnell Douglas Corporation
    Inventor: William T. Walls
  • Patent number: 5798463
    Abstract: A tensile test fixture for applying constant tensile forces to a tensile test specimen comprises two mounting grips, each mounted to one of two lever arms in a pivoted lever arm frame structure. One end of each lever arm is pivotally attached to a compression column while the other end of each lever arm is attached to one end of a force-applying assembly. The mounting grips are pivotally attached to their respective lever arms between the compression column and the force-applying assembly and are designed to hold opposite ends of a tensile test specimen. The force-applying assembly comprises stress and strain modules that are interchangeably installable into the force-applying assembly to selectively subject tensile test specimens to constant strain and constant stress.
    Type: Grant
    Filed: February 12, 1997
    Date of Patent: August 25, 1998
    Assignees: Automotive Composites Consortium, University of Tulsa
    Inventors: John C. Doudican, Edward M. Hagerman, John M. Henshaw, Laura J. Meyer, Daniel Q. Houston
  • Patent number: 5723793
    Abstract: Methods and apparatus are disclosed for measuring stress and strain of microscopic specimens under a microscope. The measurements of strain can be performed simultaneously with measurement of the stress, thereby avoiding problems with creep. The apparatus and methods employ an electrically driven microgripper having at least one finger adapted to contact the specimen. The apparatus and methods also employ a device operable to measure the dimensional change (strain) experienced by the specimen upon application of a stress to the specimen using the finger(s) of the microgripper. From measurements of electrical energy supplied to the microgripper before and during application of the stress to the specimen, and of the stress-caused dimensional change of the specimen, stress-versus-strain information about the specimen can be calculated.
    Type: Grant
    Filed: January 15, 1997
    Date of Patent: March 3, 1998
    Assignee: Nikon Corporation
    Inventors: Yoshihiko Suzuki, Takashi Kawahito
  • Patent number: 5691481
    Abstract: A method is disclosed for obtaining data on the strain-stress relation of a test piece of molding sand under a varying load to predict the degree of deformation of a green sand mold which is caused after the green sand mold is moved or filled with molten metal. The test piece of molding sand for a green sand mold is produced by compressing the molding sand. The varying load, and varying length of the test piece under the varying load, are measured at short intervals. Based on the measurements, the strain-stress relation of the test piece is calculated and then the data is stored. The stored data is used to predict the degree of deformation of a green sand mold produced from the same molding sand that is tested.
    Type: Grant
    Filed: December 1, 1995
    Date of Patent: November 25, 1997
    Assignee: Sintokogio, Ltd.
    Inventor: Tadashi Nishida
  • Patent number: 5569858
    Abstract: A system for performing a flexometer test includes a balanced beam supporting an anvil upon which a viscoelastic material is placed, the balanced beam being balanced upon a rotatable shaft and pivotable about the axis of the rotatable shaft, an assembly for applying a static load to the material, a hammer opposite the anvil for applying a dynamic strain to the material, and a sensor which senses permanent dimensional changes in the material.
    Type: Grant
    Filed: August 22, 1995
    Date of Patent: October 29, 1996
    Assignee: The B. F. Goodrich Company
    Inventors: Donald W. Askea, Jeffrey W. Johnson
  • Patent number: 5532023
    Abstract: The present invention relates to a wrinkle reducing composition for use on fabrics, particularly clothing. The composition comprises a wrinkle reducing active, which is made up of an effective amount of silicone and an effective amount of film-forming polymer, and a liquid carrier. The composition is substantially free of starch, modified starch, and mixtures thereof, and results a Loss Modulus Difference of greater than about 3.3.times.10.sup.7 Pascal on fabric.The composition can be incorporated into a spray dispenser that can create an article of manufacture than can facilitate treatment of fabric with the wrinkle reducing composition. The wrinkle reducing actives in the composition can be determined through Dynamic Mechanical Analysis using a 100% cotton broadcloth swatch and a fixed volume of a sample of wrinkle reducing active.
    Type: Grant
    Filed: November 10, 1994
    Date of Patent: July 2, 1996
    Assignee: The Procter & Gamble Company
    Inventors: Alice M. Vogel, Errol H. Wahl, Jerome P. Cappel, Thomas C. Ward
  • Patent number: 5517860
    Abstract: Measurement of stress-strain relationships in thin films using substantially flat, parallel test surfaces with minimal width.
    Type: Grant
    Filed: February 3, 1995
    Date of Patent: May 21, 1996
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Li Lin, Melvin H. Johnson
  • Patent number: 5495771
    Abstract: There are provided an elasticity measuring method of measuring an elastic constant of elasticity of an elastic body, for example, an elastic rubber, an organism or a living body, etc., which is soft and rather incompressible, by means of measuring an internal strain using energy such as ultrasounds, an X-ray, and magnetism, where the elastic constant includes, for example, typically shear modulus, Young's modulus, etc.; and an elasticity measuring apparatus adapted to practice such an elasticity measuring method. According to such method and apparatus, the elastic constant distribution within the subject is detected only through measuring the strain distribution within the subject, without measuring the stress distribution.
    Type: Grant
    Filed: April 28, 1994
    Date of Patent: March 5, 1996
    Assignees: Kiyoshi Nakayama, Fujitsu Limited
    Inventors: Chikayoshi Sumi, Kiyoshi Nakayama
  • Patent number: 5461925
    Abstract: Keratin fiber condition is evaluated by testing dry hair to determine analysis factors. For each factor, two values of elongation are determined by measuring the force required to obtain a first value and a second value of elongation of the fiber. The percent total elongation of the fiber to its break point is also determined. The ratio of the two measured forces is used with the percent total elongation in empirically derived nonlinear equations to determine analysis factors, such as a condition factor and a moisture factor. It is found that each factor is independent of fiber diameter or the source of the fiber. It is also found that the factors change as a function of subjective or objective measures of chemical damage to, and moisture content of, the hair fiber. The factors can, therefore, be used for identifying hair care products suitable for application to the hair without inducing unacceptable damage.
    Type: Grant
    Filed: March 28, 1994
    Date of Patent: October 31, 1995
    Assignee: Redken Laboratories, Inc.
    Inventors: Nghi V. Nguyen, David W. Cannell, Roger A. Mathews