Abstract: A device for analysis of mechanical and thermal loading of structures can include: a first member comprising first material; a second member comprising second material; and a third member comprising the first material. The second member can be fastened at least partially between the first and third members. The device can be configured to mechanically load the first, second, and third members by applying equal and opposite force to protruding ends of the first, second, and third members. A device for analysis of mechanical and thermal loading of structures can include: a first member comprising first material; and a second member comprising second material. The first member can be fastened at least partially between portions of the second member. The device can be configured to mechanically load the first and second members by applying equal and opposite force to protruding ends of the first and second members.

Abstract: A tension load fixture for applying tension or loading forces to a specimen comprises a pair of tension arms and an imaging device. The pair of tension arms are configured to releasably couple to opposite end regions of a specimen and to apply tension or loading forces to the specimen. The specimen is configured to be positioned between the pair of tension arms and defines a notch between the opposite end regions. The notch extends from a side of the specimen to a middle region of the specimen. The imaging device is configured to capture one or more images of the middle region and is configured to rotate about a central axis of the tension load fixture that is proximate to the middle region to facilitate generation of a three-dimensional image of the middle region as the specimen is subjected to tension or loading forces.

Abstract: A method for determining fatigue properties of a structure includes mounting the structure in a load frame. The structure has a crack with a crack size. The method includes applying repeatedly an adjustable stimulus to the structure over multiple cycles. The adjustable stimulus is an adjustable load or an adjustable displacement applied to the structure. The method further includes storing the crack size at a start of the cycles, measuring a response of the structure subjected to the adjustable stimulus in each cycle, updating the crack size based on the response in each cycle, and updating the adjustable stimulus in each cycle. The adjustable stimulus as updated maintains a strain energy release rate approximately constant based on the crack size. The method includes calculating a growth rate of a crack propagation in the structure based on the response in each cycle, and storing the growth rate in a file.

Abstract: A tension load fixture for applying tension or loading forces to a specimen comprises a pair of tension arms and an imaging device. The pair of tension arms are configured to releasably couple to opposite end regions of a specimen and to apply tension or loading forces to the specimen. The specimen is configured to be positioned between the pair of tension arms and defines a notch between the opposite end regions of the specimen. The notch extends from a side of the specimen to a middle region of the specimen. The imaging device is configured to capture one or more images of the middle region of the specimen and is configured to rotate about a central axis of the tension load fixture that is proximate to the middle region of the specimen to facilitate generation of a three-dimensional image of the middle region of the specimen as the specimen is subjected to tension or loading forces.

Abstract: A method for analysis of a fastened structure includes accessing an electronic design model of the fastened structure, embedding at least one sensor element model within the electronic design model, applying at least one simulated load to the electronic design model, monitoring the measurement parameters using the at least one sensor element model to detect load conditions at the corresponding select location based on the at least one simulated load; and comparing the detected load conditions to predetermined measurement thresholds for the monitored measurement parameters. A fastened structure management system includes a computing system and a storage device in operative communication with the computing system. An analytical computing system for analysis of a fastened structure includes at least one processor and associated memory, at least one electronic storage device and a network interface.

Abstract: A device for analysis of mechanical and thermal loading of structures can include: a first member comprising first material; a second member comprising second material; and a third member comprising the first material. The second member can be fastened at least partially between the first and third members. The device can be configured to mechanically load the first, second, and third members by applying equal and opposite force to protruding ends of the first, second, and third members. A device for analysis of mechanical and thermal loading of structures can include: a first member comprising first material; and a second member comprising second material. The first member can be fastened at least partially between portions of the second member. The device can be configured to mechanically load the first and second members by applying equal and opposite force to protruding ends of the first and second members.

Abstract: A method for determining fatigue properties of a structure includes mounting the structure in a load frame. The structure has a crack with a crack size. The method includes applying repeatedly an adjustable stimulus to the structure over multiple cycles. The adjustable stimulus is an adjustable load or an adjustable displacement applied to the structure. The method further includes storing the crack size at a start of the cycles, measuring a response of the structure subjected to the adjustable stimulus in each cycle, updating the crack size based on the response in each cycle, and updating the adjustable stimulus in each cycle. The adjustable stimulus as updated maintains a strain energy release rate approximately constant based on the crack size. The method includes calculating a growth rate of a crack propagation in the structure based on the response in each cycle, and storing the growth rate in a file.

Abstract: A computer is configured to generate a computer model predicting the progressive creation, density, and spacing of a plurality of cracks in a filler material, such as a “noodle,” for example, disposed at a connection interface between a load-bearing composite structural component, such as a stringer or a spar, for example, and the structural framework of a vehicle on which those structural components are utilized.

Abstract: An example method includes determining, by a computing system, a dry thickness of a fabric preform. The method also includes determining, by the computing system, a debulked thickness of the fabric preform using the dry thickness of the fabric preform. In addition, the method includes determining, by the computing system, a stitch tension using the dry thickness of the fabric preform and the debulked thickness of the fabric preform. And the method includes causing, by the computing system, a stitching machine to apply a through-the-thickness stitch having the stitch tension to the fabric preform.

Abstract: A computer-implemented method facilitates receiving, by a computing system, one or more parameters that specify attributes associated with a bonded joint and, in particular, a type of bonded joint. The computing system selects from a model template repository one or more bonded joint model templates associated with the type of bonded joint. The computing system generates a bonded joint model based on the bonded joint model templates and the parameters. The bonded joint model facilitates the performance of finite element analysis (FEA). FEA logic of the computing system simulates the application of stress to the bonded joint model. The FEA logic of the computing system determines a change in a size of a defect that results from the application of stress to the bonded joint model. The computing system determines, based on the change in the size of the defect, the life expectancy of the bonded joint.

Abstract: A tension load fixture for applying tension or loading forces to a specimen comprises a pair of tension arms and an imaging device. The pair of tension arms are configured to releasably couple to opposite end regions of a specimen and to apply tension or loading forces to the specimen. The specimen is configured to be positioned between the pair of tension arms and defines a notch between the opposite end regions of the specimen. The notch extends from a side of the specimen to a middle region of the specimen. The imaging device is configured to capture one or more images of the middle region of the specimen and is configured to rotate about a central axis of the tension load fixture that is proximate to the middle region of the specimen to facilitate generation of a three-dimensional image of the middle region of the specimen as the specimen is subjected to tension or loading forces.

Abstract: An example method includes determining analytical material properties indicative of an effective fracture behavior of a through-thickness reinforcement. The method also includes obtaining data defining a cohesive formulation within a finite element analyzer. The cohesive formulation is representative of the through-thickness reinforcement, and the data defining the cohesive formulation is derived from the analytical material properties. The method further includes generating a finite element model for the composite structure. The composite structure includes the through-thickness reinforcement, and the finite element model represents the through-thickness reinforcement using the cohesive formulation. The method also includes analyzing a mechanical performance of the composite structure using the finite element analyzer and the finite element model, and outputting data indicative of the mechanical performance of the composite structure.

Abstract: Systems, apparatuses and methods provides for technology that generates a plurality of discrete and finite elements associated with a component, where a number of the plurality of discrete and finite elements corresponds to a size of an estimated process zone. The technology further identifies material input properties of the component, models crack propagation throughout the plurality of discrete and finite elements based on the material input properties and models a release response in the plurality of discrete and finite elements based on the material input properties.

Abstract: An example method includes determining, by a computing system, a dry thickness of a fabric preform. The method also includes determining, by the computing system, a debulked thickness of the fabric preform using the dry thickness of the fabric preform. In addition, the method includes determining, by the computing system, a stitch tension using the dry thickness of the fabric preform and the debulked thickness of the fabric preform. And the method includes causing, by the computing system, a stitching machine to apply a through-the-thickness stitch having the stitch tension to the fabric preform.

Abstract: A method, apparatus, and system for managing a composite structure. A set of component models is created for a set of components in the composite structure. A set of embedded reinforcement element models is placed within the set of component models for the set of components in the composite structure to form a composite structure model for the composite structure. The set of embedded reinforcement element models is for a set of embedded reinforcements embedded within the set of components in the composite structure. A structural analysis of the composite structure is performed using the composite structure model formed by the set of component models and the set of embedded reinforcement element models, wherein the set of embedded reinforcement element models enables modeling at least one of a deformation or a failure of embedded reinforcements.

Abstract: A method includes obtaining failure initiation characteristics of a bonding layer of one or more bonded structures and determining, based on the failure initiation characteristics, a first characteristic dimension for each analysis element of a first portion of a finite element analysis model. The method includes obtaining failure propagation characteristics of the bonding layer and determining, based on the failure propagation characteristics, a second characteristic dimension for each analysis element of a second portion of the model. The method includes assigning a first set of material parameters to analysis elements of the first portion of the model and assigning a second set of material parameters to analysis elements of the second portion of the model. The method includes evaluating failure modes of the one or more bonded structures based on a solution to the model, the first set of material parameters, and the second set of material parameters.

Abstract: A method, apparatus, and system for managing a composite structure. A set of component models is created for a set of components in the composite structure. A set of embedded reinforcement element models is placed within the set of component models for the set of components in the composite structure to form a composite structure model for the composite structure. The set of embedded reinforcement element models is for a set of embedded reinforcements embedded within the set of components in the composite structure. A structural analysis of the composite structure is performed using the composite structure model formed by the set of component models and the set of embedded reinforcement element models, wherein the set of embedded reinforcement element models enables modeling at least one of a deformation or a failure of embedded reinforcements.

Abstract: A load frame for applying a tensile load to a test sample during a test or measurement includes a first gripper for gripping a first end of the test sample, a second gripper for gripping a second end of the test sample, and a tensioner for applying the tensile load to the test sample. The load frame further includes a first end tube that encircles the first gripper, a second end tube that encircles the second gripper, and a center tube that encircles a mid-portion of the test sample during the test or measurement. A system such as a wave-generating system may be used to measure the test sample through the center tube during a test or measurement.

Abstract: A method includes obtaining failure initiation characteristics of a bonding layer of one or more bonded structures and determining, based on the failure initiation characteristics, a first characteristic dimension for each analysis element of a first portion of a finite element analysis model. The method includes obtaining failure propagation characteristics of the bonding layer and determining, based on the failure propagation characteristics, a second characteristic dimension for each analysis element of a second portion of the model. The method includes assigning a first set of material parameters to analysis elements of the first portion of the model and assigning a second set of material parameters to analysis elements of the second portion of the model. The method includes evaluating failure modes of the one or more bonded structures based on a solution to the model, the first set of material parameters, and the second set of material parameters.

Abstract: A computer is configured to generate a computer model predicting the progressive creation, density, and spacing of a plurality of cracks in a filler material, such as a “noodle,” for example, disposed at a connection interface between a load-bearing composite structural component, such as a stringer or a spar, for example, and the structural framework of a vehicle on which those structural components are utilized.