Abstract: Performance of a sport equipment, such as a ball bat, is measured by applying a force through a spring of known elastic properties to compress the sport equipment and indicating compliance of the sport equipment to a known standard based on the compression of the sport equipment.

Abstract: An apparatus is provided for measuring the unconfined yield strength and time unconfined yield strength of bulk granular materials and powders. A sample of bulk material is consolidated under controlled pressure in a sample cup with a hole or holes in the bottom. A moveable base smaller than the internal cup dimensions covers the hole(s) to prevent material from escaping the cup and to provide a base for removing the consolidated sample from the cup. After a predetermined time, the consolidated sample is removed from the cup by lifting the base relative to the cup walls through the hole(s) in the bottom of the cup. Once removed from the cup, the strength of the consolidated sample is measured by applying pressure to the top of the sample until the sample breaks. For time tests, the sample is consolidate with weights over predetermined time periods.

Abstract: An apparatus for determining a magnitude of a compressive load applied to a piston including a compliant film disposed between first and second elements is provided. The apparatus includes a first part movable with the first element in a movement direction along which the magnitude of the compressive load is to be determined, a second part movable with the second element in the movement direction and a sensor to measure a distance between the first and second parts in the movement direction, the measured distance being related to a deformation of the compliant film as the compressive load is applied.

Abstract: The invention provides a forming and wrapping unit (2) for forming material into a continuous bar (20) and wrapping said material the unit comprising: a forming chamber (6) for forming material into a continuous bar; sheet wrapping means (4) for wrapping said continuous bar; and control means operating on said sheet wrapping means, wherein said sheet wrapping means and said control means are adapted to be operable independently of a rate of feeding bulk material into the forming chamber. The invention also relates to a method for forming and wrapping material into a continuous bar, comprising feeding said material to a wrapping position while forming said material; wrapping sheet around said material such that said sheet at least partly overlaps a previously wrapped round of sheet; and transferring the wrapped material from said wrapping position to a storage ready position. The step of feeding the material to a wrapping position and said step of wrapping sheet around the material are separately operable.

Abstract: A fixture facilitates using a linear force of a uni-axial test machine to subject a test sample to bending forces. The test machine includes a frame and a crosshead. To generate the linear force, the crosshead translates with reference to the frame in a plane of motion. The fixture includes an upper connecting link, a lower connecting link, and two transverse arms. The upper connecting link is configured to attach to the crosshead for receiving the linear force, and the lower connecting link is configured to attach to the frame. The two transverse arms are pivotably carried between the upper and lower links. Each transverse arm has an inner end configured to attach to the test sample, the test sample being suspended between the arms. The transverse arms pivot in opposite directions in response to the linear force applied to the upper connecting link, exposing the sample to bending forces.

Abstract: Performance of a sport equipment, such as a ball bat, is measured by applying a force through a spring of known elastic properties to compress the sport equipment and indicating compliance of the sport equipment to a known standard based on the compression of the sport equipment.

Abstract: A method for calibrating a gyratory compactor apparatus is provided. The gyratory compactor apparatus is of the type being configured to compact and impart an orbital motion to a sample in a mold that defines a mold axis and includes at least one actuator for imparting lateral displacement of the mold relative to a longitudinal axis of the gyratory compactor apparatus. The method includes the steps of imparting lateral orbital displacement of the mold relative to the gyratory compactor apparatus by actuation of the at least one actuator to thereby define a gyratory angle between the gyratory compactor apparatus and the mold axis, measuring the gyratory angle, and determining adjustments to actuation of the at least one actuator based on the measured gyratory angle and a target angle. An associated apparatus and method for calibrating the apparatus are also included.

Abstract: Improved apparatuses and methods for testing turf or other surfaces, in one embodiment, a turf testing apparatus includes two actuators for moving a shoe relative to a turf surface. The first actuator moves the shoe along a substantially horizontal axis and the second actuator moves the shoe along a substantially vertical axis.

Abstract: A method for estimating the state of a battery having multiple cells is disclosed. In one embodiment, strain gauges are coupled to battery binding bands that hold cells of the battery together. The strain measured by the gauges may be related to the electrical charge stored by the battery. The method may improve estimates of battery state of charge during conditions when battery voltage changes little and the battery continues to accept charge.

Abstract: A fixture for testing a tubular member simultaneously in bending and torsion is disclosed. The fixture includes first and second attachment elements that are configured to couple to the tubular member, and a load shoe that is configured to fit within the tubular member. The load shoe includes a body having a contact surface configured to contact a portion of an internal surface of the tubular member and at least one load reaction strut coupled to the body. The load reaction strut is configured to pass through a hole in the tubular member and accept a first force applied in a first direction that is perpendicular to an axis of symmetry of the tubular member.

Abstract: The present invention provides a microtesting rig for measuring mechanical properties of small specimens. The rig includes a microsized specimen positioned on a mounting block, an interchangeable contact tip connected with an actuator and configured for contact with the microsized specimen, and a magnifying imaging system for imaging the microsized specimen. The contact tip may be a fiber platen for compression testing or a fiber grip for tension testing.

Abstract: The present invention relates to a Test apparatus (10) for testing the interaction between through-thickness compression and shear in a test piece (16). The apparatus comprises first and second chocks (12, 14) arranged in use to securely retain a test piece, and first and second races (18, 20) which can be controllably urged towards each other to transmit a known force to the first and second chocks. The first and second chocks and the test piece together form a substantially cylindrical body of a first diameter and. The first and second races define therebetween a substantially cylindrical space of a second diameter for accommodating the chocks, and wherein the second diameter is greater than the first diameter.

Abstract: A flexible pressure sensor has a first set of substantially parallel conductors in the x direction, a second set of substantially parallel conductors in the y direction, and a composite material disposed between the first set and second set of conductors. The composite material is capable of returning to substantially its original dimensions on release of pressure. The composite material includes conductive particles at least partially embedded in an elastomeric layer that have no relative orientation and are disposed within the elastomeric layer for electrically connecting the first set and second set of conductors in the z direction under application of sufficient pressure there between.

Abstract: A load device for planar solid oxide fuel cell stack comprises: a balance plate, a high-temperature compressed column, a load cell, an elastic member, an equalizing ring, and an actuator. The balance plate is disposed abutted against the fuel cell stack, and the high-temperature compressed column is disposed on the balance plate, and the load cell and the elastic member are arranged at a top portion of the high-temperature compressed column. The actuator, being placed on the equalizing ring, is used for providing a load to the equalizing ring, the load cell, the elastic member and the high-temperature compressed column Thereby, the load exerted by the actuator can be detected from the measurement of the load cell while the relationship between the load variation and performance of the SOFC stack can be read directly or transmitted to an external device for display.

Abstract: The device is used to perform component and material tests on samples, in particular compression tests and tensile tests on springs and elastic components, assemblies, and material samples. The device comprises two sample retainers (2.1, 2.2) arranged opposite each other, between which sample retainers a force for loading the sample (1) arranged therebetween can be generated, wherein one sample retainer (2.1) is fixed to a base frame (3) and the other sample retainer (2.2) is arranged on a movable adjusting element (4). Furthermore, the device is provided with a displacement recorder (6) that detects the travel of the sample retainer (2.2) by means of a displacement sensor (5) and a force transducer (7) that detects the force applied to the sample (1). The adjusting element (4) comprises a hollow-drilled spindle (8), which surrounds the displacement sensor (5) at a small distance and which is connected to the sample retainer (2.

Abstract: A compression testing assembly for compression testing of a test material includes a testing stage with a first surface and a second surface. The test material is disposed between the first and second surfaces. The assembly also includes a thickness detector that automatically detects a thickness of the test material. Moreover, the assembly includes an actuator that moves at least one of the first and second surfaces toward the other of the first and second surfaces to compress the test material to a predetermined percentage of the detected thickness of the test material. Additionally, the assembly includes a load detector that detects a compression load of the test material and that detects a change in the compression load over time.

Abstract: An apparatus for testing strength of a corner portion of an object includes a support platform, an installing mechanism on the platform, a force gauge, a driving mechanism connected to the slidable plate to move the slidable plate, a clamp mechanism for clamping the object in a fixed position, and a push-pull mechanism. The installing mechanism includes two opposite rail plates mounted to the platform, and a slidable plate slidably mounted between the rail plates. The force gauge is fixed to the slidable plate. The push-pull mechanism is connected to the force gauge to be pushed or pulled by the force gauge. The push-pull mechanism comprises two forcing posts to respectively abut against two sides of the object at the corner portion, thereby exerting push or pull force on the two sides of the corner portion to test strength of the corner portion.

Abstract: A device for measuring the spring rate of a golf ball is disclosed. The device receives a golf ball between a first anvil and a second anvil. A force gauge is provided on one anvil. A displacer is provided on another anvil. Each anvil defines a ball receiving depression that is larger than the dimples of the golf ball to be measured for negating measurement effects due to golf ball dimples when measurement of the golf ball is conducted. The displacement an anvil is determined. From the force data and displacement data, a spring rate of the golf ball can be calculated and a compression scale value may be calculate and displayed on the device for informing a golfer that is operating the hand held device.

Abstract: A fatigue test system for repetitively deforming a substantially tubular implant structure which is within a radial range and within an axial range expandable and contractable and which has at least a first and a second end, wherein the system comprises at least a first and second part which are controllably moveable relative to each other, and a first and a second fixture assembly for fixing the first end to the first part and the second end to the second part, so that the system controls in use the position of each of the first and second end of the tubular implant structure.

Abstract: Apparatus are provided for sensor assemblies and related medical devices. An embodiment of a sensor assembly includes a rigid structure and a beam structure having an outer portion in contact with the rigid structure and an inner portion. The beam structure includes one or more beams extending between the outer portion and the inner portion of the beam structure and a cantilevered portion extending from the inner portion to inhibit displacement of the inner portion toward the rigid structure. Each beam has a sensing element disposed thereon.

Abstract: A system and method for determining the compressive strength of pellets are presently disclosed. A system includes a moveable feed tray adapted to support a plurality of pellets to be tested, a platen below the moveable feed tray and opposite a ram capable of applying compressive force to a pellet, a drive motor engaging the moveable feed tray, and a compressive force monitoring system including a force sensor. A method includes providing a feed tray and positioning a ram at a first position above a platen, advancing the feed tray to position a pellet at a test position between the ram and the platen, detecting the non-arrival of the pellet at the test position, retracting the ram from the first position, advancing the feed tray and operating the ram to determine the compressive strength of the pellet. Also disclosed is a calibration method for a compression test system.

Abstract: The present invention pertains to systems and methods for measuring power output, as in an athletic activity such as cycling. One embodiment relates to a force sensing device configured to be mounted on the bottom surface of a shoe as part of a mechanical linkage through which force is exerted. For cycling, the force sensor is mounted on the bottom surface of a cycling shoe and fitted with a cleat that interlockingly engages a bicycle pedal. To measure both positive and negative pressures on the pedal, the force sensor is pre-stressed with a compressive load to an intermediate point in its dynamic range. Strains that further compress or decompress the force sensor can thus be measured. The computing module mathematically converts the measured pressures, positive and negative, to a measurement of total power exerted by the rider. In addition, the computing module may utilize cyclical regularities in the signal to compute the rider's cadence (pedal revolutions per unit of time).

Abstract: A method of testing a transformer prior to installation in a high-pressure environment wherein the transformer comprises a transformer core comprising a stack of a plurality laminations, is provided. The method comprises applying a mechanical compression force to the stack, the force being at least equivalent to the ambient pressure of the high-pressure environment; and testing the electrical efficiency of the transformer.

Abstract: A gyratory compactor apparatus adapted to interact with a mold that defines a mold axis is provided. The gyratory compactor apparatus includes a frame defining a frame axis and having a first mounting plate and a pivoted support carried by the frame and capable of rotation in at least a first and a second rotational degree of freedom. A mold-engaging device is carried by the pivoted support and includes a first carriage plate proximal the pivoted support and a spaced-apart second carriage plate that defines a space therebetween for receiving the mold. The second carriage plate has at least one clamping rod in communication with an actuator for translating the second carriage plate about the mold axis to thereby secure the mold in the space between the first and second carriage plates. An associated method is also provided.

Abstract: A reduction in cost and improvement in evaluation accuracy are achieved.

Abstract: The present invention is a device for testing the mechanical properties of a specimen. The device includes an actuator component slider for positioning the specimen within one of multiple test configuration positions, such that each test configuration position examines the static compression/tension properties, dynamic compression/tension properties, static torsional properties, or dynamic torsional properties of the specimen.

Abstract: Methods of assessing three dimensional fabric feel are useful for identifying fabric care actives.

Abstract: Disclosed are systems and methods for evaluating the properties of material used in the manufacture of pulling rolls. In one embodiment, a method is provided for aligning plates comprising the material along an axis and compressing the plates to form a cartridge. The plates can be compressed by a piston. The cartridge can be rotated by a motor. In one embodiment, the cartridge, while rotating, is contacted with a cutting surface to produce a surface finish on the cartridge. Properties such as compressibility, recovery and resiliency, and hardness can be measured.

Abstract: A test fixture for use with a Dynamic Mechanical Analyzer (DMA) restrains a hollow cylindrical tube for purposes of performing either a tensile or transverse/bending load test. The fixture includes a clamp that is configured to restrain the tube without imparting a preload or changing a mechanical property of the tube.

Abstract: An edge-strength measuring device for measuring the compressive strength of a foam matrix along the edges thereof, the device comprising at least one measuring implement having one or more contacting elements for engaging with the edges of the foam matrix, and at least one measuring device in communication with said contacting elements for measuring the resistance imparted by the foam matrix when said contacting element is engaged with the edge.

Abstract: An apparatus for and method of measuring the compressed volume of a particulate material comprising a chamber for containing a particulate material which will be evaluated; a removable, fixed means at one end of said chamber to enclose said chamber and for containing said particulate material within said chamber; a compression means at the other end of said chamber which further encloses and contains said particulate material within said chamber and which provides a linear force on said particulate material so that one end of said particulate material is linearly movable and said compression means will compress the particulate material in said chamber; means to move said moveable piston away from a particulate material placed inside said chamber to decompress the particulate material in said chamber; means for measuring the distance between said movable piston and said fixed means so to measure the thickness of said compressed particulate material; and measuring means on the moveable piston of said chamber fo

Abstract: Disclosed is an integrated multi-measurement system for measuring physical properties including thickness, electrical resistance and differential pressure of a gas diffusion layer for a polymer electrolyte fuel cell with respect to compression. The integrated multi-measurement system simultaneously measures changes in the physical properties of the gas diffusion layer depending on pressure upon measurement of the physical properties of the gas diffusion layer of the fuel cell and also measures through-plane permeability in which a gas is passed through a sample in a direction perpendicular to the sample and in-plane permeability in which a gas is passed through a sample in a direction parallel to the sample.

Abstract: A pressing head structure (100) for testing key durability includes a pressing mechanism (10), a rubber head (40), a connecting mechanism (20) and a balance mechanism (30). The pressing mechanism includes a sliding rod (12) and a first spring (16). The first spring is placed over the sliding rod. The connecting mechanism connects the pressing mechanism and the rubber head. The balance mechanism is rotatably fixed to the connecting mechanism. The balance mechanism engages with the pressing mechanism. When the sliding rod moves down, the first spring and the balance mechanism together supply an unaltered resultant resistance in the moving direction of the sliding rod.

Abstract: A method and means for determining a critical elongation strain rate of a polymer melt, which make it possible to subject a polymer melt to elongation to prepare a bulk oriented melt, are established, and a process for producing bulk polymer oriented crystals and polymer oriented crystals are provided. In the critical elongation strain rate determination process or critical elongation strain rate determining method, a polymer melt (3) in a disc shape having a radius x0 and a thickness of ?z0 is held between transparent plates (an upper transparent plate (1) and a lower transparent plate (2)). The polymer melt (3) is cooled to a supercooled state and is press in a thickness direction at a constant rate v by using the transparent plates. The critical point radius x*, at which the polymer melt (3) is turned to an oriented crystal, is measured, and the critical elongation strain rate ? is calculated by equation ?*=ax*3 wherein ?=v/(2?z0x03).

Abstract: The present invention relates to a Test apparatus (10) for testing the interaction between through-thickness compression and shear in a test piece (16). The apparatus comprises first and second chocks (12, 14) arranged in use to securely retain a test piece, and first and second races (18, 20) which can be controllably urged towards each other to transmit a known force to the first and second chocks. The first and second chocks and the test piece together form a substantially cylindrical body of a first diameter and. The first and second races define therebetween a substantially cylindrical space of a second diameter for accommodating the chocks, and wherein the second diameter is greater than the first diameter.

Abstract: Performance of a sport equipment, such as a ball bat, is measured by applying a force through a spring of known elastic properties to compress the sport equipment and indicating compliance of the sport equipment to a known standard based on the compression of the sport equipment.

Abstract: An apparatus for testing strength of a corner portion of an object includes a support platform, an installing mechanism on the platform, a force gauge, a driving mechanism connected to the slidable plate to move the slidable plate, a clamp mechanism for clamping the object in a fixed position, and a push-pull mechanism. The installing mechanism includes two opposite rail plates mounted to the platform, and a slidable plate slidably mounted between the rail plates. The force gauge is fixed to the slidable plate. The push-pull mechanism is connected to the force gauge to be pushed or pulled by the force gauge. The push-pull mechanism comprises two forcing posts to respectively abut against two sides of the object at the corner portion, thereby exerting push or pull force on the two sides of the corner portion to test strength of the corner portion.

Abstract: A gyratory compactor apparatus adapted to interact with a mold that defines a mold axis is provided. The gyratory compactor apparatus includes a frame defining a frame axis and having a first mounting plate and a pivoted support carried by the frame and capable of rotation in at least a first and a second rotational degree of freedom. A mold-engaging device is carried by the pivoted support and includes a first carriage plate proximal the pivoted support and a spaced-apart second carriage plate that defines a space therebetween for receiving the mold. The second carriage plate has at least one clamping rod in communication with an actuator for translating the second carriage plate about the mold axis to thereby secure the mold in the space between the first and second carriage plates. An associated method is also provided.

Abstract: A method for calibrating a gyratory compactor apparatus is provided. The gyratory compactor apparatus is of the type being configured to compact and impart an orbital motion to a sample in a mold that defines a mold axis and includes at least one actuator for imparting lateral displacement of the mold relative to a longitudinal axis of the gyratory compactor apparatus. The method includes the steps of imparting lateral orbital displacement of the mold relative to the gyratory compactor apparatus by actuation of the at least one actuator to thereby define a gyratory angle between the gyratory compactor apparatus and the mold axis, measuring the gyratory angle, and determining adjustments to actuation of the at least one actuator based on the measured gyratory angle and a target angle. An associated apparatus and method for calibrating the apparatus are also included.

Abstract: A gyratory compactor apparatus is provided that is adapted to interact with a mold that defines a mold axis. The gyratory compactor apparatus includes a frame that defines a frame axis and has a first mounting plate and a spaced-apart second mounting plate. A pivoted support is carried by the frame and capable of rotation in at least a first and a second rotational degree of freedom. A mold-engaging device is carried by the pivoted support and has a first carriage plate proximal the pivoted support and a second carriage plate axially spaced-apart from the pivoted support for receiving the mold therebetween. At least one actuator having a first end is carried by the frame and a second end is carried by the second carriage plate for imparting lateral translation to the second carriage plate relative to the frame axis. An associated method is also provided.

Abstract: A test device for an electronic product includes a vertical pressing pole having a pushing end. The test device also includes a movable platform with a sticking point, wherein upward movement of the movable platform moves the vertical pressing pole upwards by the sticking point. The vertical pressing pole passes through a balance weight which rests on the sticking point. A pressurized platform bears pressure from the pushing end, when the pushing end is pushed onto the pressurized platform. A load-bearing platform supports the pressurized platform and the electronic product located below the pressurized platform. The product is pressed between the pressurized platform and the load-bearing platform due to the pressure from the pushing end lying on the pressurized platform. When the movable platform is further moved downwards after the pushing end is on the pressurized platform, the sticking point bearing the balance weight is separate from the movable platform.

Abstract: A test structure for dynamic seat tests comprises a load cell, a seat rail with a bar and a upper chord, a load transfer device, which comes into contact with opposite sides of the bar of the seat rail and is fixed to the load cell and an integrated floor plate which is fixed to the upper chord of the seat rail and to the load transfer device.

Abstract: Disclosed is an integrated multi-measurement system for measuring physical properties including thickness, electrical resistance and differential pressure of a gas diffusion layer for a polymer electrolyte fuel cell with respect to compression. The integrated multi-measurement system simultaneously measures changes in the physical properties of the gas diffusion layer depending on pressure upon measurement of the physical properties of the gas diffusion layer of the fuel cell and also measures through-plane permeability in which a gas is passed through a sample in a direction perpendicular to the sample and in-plane permeability in which a gas is passed through a sample in a direction parallel to the sample.

Abstract: An automatic keyboard inspection apparatus, adapted for inspecting a keyboard, is disclosed, which comprises: a retractable device, a pressing part, a path control unit and a dual-axial platform; wherein, as the automatic keyboard inspection apparatus is enabled to operate in a first mode, the retractable device will activate a linkage rod to move axially so as to trigger the pressing part to drop by the gravity and thus press upon a specific key of the keyboard; and as the automatic keyboard inspection apparatus is enabled to operate in a second mode, specifying a route of a specific traveling distance, the pressing part is direct to travel and fall following the specified route to press upon the specific key; and the dual-axial platform, being adapted for carrying the keyboard, is able to perform a bi-axial movement with respect to a 2-D Cartesian coordinates of X, Y axes so as to enable the pressing part to drop and press on four different corners of the specific key for testing the same.

Abstract: The submarine phenomenon can be prevented and the accuracy of a passenger's weight measurement is improved. A vehicle seat 1 comprises a pair of fixed lower rails 3 fixed on the floor of a passenger compartment, a pair of movable upper rails 4 which are engaged with the fixed lower rails 3 so as to be slidable in a front-and-rear direction with respect to each of the fixed lower rails 3, a sub frame 110 which is disposed at an upper side of the movable upper rails 4, load sensors 50, 60, 70, and 80 which lie between the sub frame 110 and the movable upper rails 4, brackets 8 and 9 which are disposed so as to erect them on each of the movable upper rails 4, and a submarine pipe 11 which is crossed between the brackets 8 and 9. The submarine pipe 11 is disposed to be slidable in a left-and-right direction with respect to the right bracket 9.

Abstract: A high suction double-cell extractor includes an outer cell defining an outer chamber, and an open-ended inner cell defining an inner chamber. The inner chamber is bottle-shaped and has a neck. The high suction double-cell extractor also includes a vertical loading system for applying axial force on a soil specimen during extraction. The high suction double-cell extractor also includes a port for introduction of pressurized air supply into the outer and inner cells. The introduced pressurized air can apply cell pressure on the soil specimen during extraction. The high suction double-cell extractor also includes a relative humidity control system and a differential pressure detector system. The high suction double-cell extractor can be used to measure stress-dependent soil-water characteristics curve (SDSWCC) under various stress states three-dimensionally and more accurately, and under total suction up to 8,000 kPa.

Abstract: A force sensor assembly particularly suited for use in an electronic stylus that senses the contact force on its nib for recording pen strokes and handwriting recognition. The sensor assembly has a housing in which force sensing circuitry is mounted. The force sensing circuitry is configured for receiving an input force to be sensed and converting the input force into an output signal indicative of the input force. A coupling transmits the input force to the force sensing circuitry. The coupling has an inner section that applies the input force to the load bearing member, an outer section that receives the contact force on the nib and a collapsible section that allows the outer section to move relative to the inner section when the contact force exceeds a threshold. The relative movement of the outer section is limited by an abutment on the housing so that the input force on the force sensing circuitry never exceeds the threshold.

Abstract: The invention is a device for dynamically load testing a sample that comprises a bearing, to which the sample can be directly or indirectly connected in a detachable manner, as well as a counter-bearing that can be effectively connected to the sample by means of at least one actuator element. The at least one actuator element introduces dynamic mechanical loads into the sample which Act along a load path that is directed between the bearing and the counter-bearing and extends through the sample. The at least one actuator element features a multifunctional solid body conversion material system that undergoes deformations due to the supply of energy, and wherein the deformations are at least one cause for the mechanical loads occurring within the sample. The device according to the invention uses at least one actuator element that may be configured in two alternative forms.

Abstract: The present invention provides a microtesting rig for measuring mechanical properties of small specimens. The rig includes a microsized specimen positioned on a mounting block, an interchangeable contact tip connected with an actuator and configured for contact with the microsized specimen, and a magnifying imaging system for imaging the microsized specimen. The contact tip may be a fiber platen for compression testing or a fiber grip for tension testing.

Abstract: A method and system for measuring radial strain on powder or other granular material while the powder is subject to compressive axial and radial loading. The powder is contained within a pliable sleeve. As pressure is applied to the powder, the sleeve changes diameter. An optical emitter emits a beam of light, which is intersected by the entire diameter of the sleeve. An optical sensor receives the intersected beam, and generates a response signal that indicates the diameter of the sleeve. This change in diameter can be related to a constitutive property such as strain.