bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Data and Knowledge Management System for Hydraulic Fixtures
Authors: Trappey Amy J. C. , Hou Jiang-Liang 
Published: January 2022

Abstract
In order to achieve an efficient integration of product information, the product data for design, manufacturing, untill logistic supports should be incorporated into a product data management (PDM) system. Specifically, large amount of manufacturing information, e.g., tooling, machining, and fixturing specifications, are determined at the production planning stage. These information need to be properly documented and managed for better production planning and control. Due to the increasing demand of modern fixture and tooling applications, this paper focuses on the construction of information system for hydraulic, automatic fixtures. Using the characteristic features of hydraulic fixtures, a data library (database) including the geometric and non-geometric information is built. By linking the database management system (DBMS) and the CAD system, information on the CAD system can be easily accessed by fixture planners. The knowledge library (knowledge base) is developed incorporating the expertise of experienced tool engineers for fixture selection. After integrating the data and knowledge libraries, the system can automatically select the suitable fixture elements according to the workpart features and machining conditions. Finally, this paper also demonstrates the system using an aerospace part as the example. The main objective of the system implementation is to reduce the fixture planning time and cost, particularly for hydraulic fixturing.
A Unified Approach to Mechanical Adhesion by Finite Element Analysis of Straight Sections
Authors: Sancaktar Erol , Narayan Kiran 
Published: January 2022

Abstract
The primary objective of this study was to optimize the geometry and volume of the substrate in lap, butt and scarf adhesive joints under various loading and boundary conditions by finite element analysis. The finite element models are validated by evaluating for convergence and by calculating theoretical values using strength of materials and applied elasticity. The results of this study are significant in optimizing mechanical adhesion because any real joint surface may contain a combination of the above model joints on a smaller scale. Studying the behavior of these basic models will help in optimizing topography of surfaces to be bonded. As a novel approach for design purposes new parameters involving stress times joint volume and stress divided by joint volume as well as stress gradients are considered. Finite element meshes of the basic lap, butt and four scarf joints (30°, 45°, 60°, 75°) having 25.4 mm adhesive length are completed. Upon validation of these models, they are subjected to various loading and boundary conditions and results obtained. Several models are created to evaluate the effect of the volume of substrate in the lap and butt joints. Considering the fact that large strain gradients result in failure, this study focuses not only on the magnitudes, but also on the gradients of stresses and strains in optimizing the joint strength. This study has concluded that there exist significant differences in the interfacial stresses with respect to the scarf angle, considering lap and butt to be special cases of scarf with 0° and 90° angles, as well as with respect to the adhesive material properties.
The Damping Characteristics of Machine Structures Assembled by Bonding: A Beam in Which Two Steel Strips Are Partially Joined by an Adhesive
Authors: Kobayashi Takashi , Nakano Yuichi 
Published: January 2022

Abstract
The purpose of this paper is to clarify the damping characteristics of adhesively bonded structures and to establish a method to estimate the damping capacity. As a fundamental study, the damping characteristics of a beam in which two steel strips are partially joined by an adhesive are investigated. Analytically, strain energy distributions are analyzed by a finite element analysis. Then, the damping capacity of the adhesively bonded beam is estimated using the strain energies and damping ratios of the two materials which are obtained independently by experiment. The validity of the proposed estimation method of the damping capacity is confirmed by experiment. The analytical results are in fairly good agreement with the experimental ones. Furthermore, the temperature dependency of the damping capacity is examined.
Stress Analysis of Bolted Circular Flanged Joints With Tap Bolts
Authors: Kobayashi Takashi , Morohoshi Tsuneshi , Sawa Toshiyuki 
Published: January 2022

Abstract
The purpose of this paper is to examine a contact stress distribution at the interface of a cylindrical clamped part fastened with a tap bolt to a body which is sufficiently larger than the clamped part. The contact stress distribution is analyzed as a contact problem of two bodies by using the axisymmetric theory of elasticity. The effect of positions of screw thread on the contact stress distribution is clarified in the numerical calculations. The load factor and the ratio of additional axial bolt force to a load are also analyzed. It is found that the contact stress becomes greater near the bolt hole when the position of screw thread is the upper. Experiments to measure the contact stress and the load factor are carried out. The analytical results show a fairly good agreement with the experimental ones. In addition, the contact stress distribution, the load factor and the maximum bolt stress of bolted circular flanged joints with multiple tap bolts are analyzed by using axisymmmetric theory of elasticity. The experiments to measure the load factor and the maximum bolt stress are carried out. A fairly good agreement is seen between the analytical and the experimental results. It is found that the value of the load factor is small and it is less than 0.1.
Low-Cycle Fatigue in Aluminum Microbeams
Authors: Vinci Richard P. 
Published: January 2022

Abstract
Cyclic plasticity and fatigue failure have long been recognized as two of the most important areas of study in bulk materials. Just like large-scale mechanical components, small-scale structures found in microelectromechanical systems are often subjected to cyclic loading. It is known that the tensile strength of thin film media on substrates can differ significantly from that of bulk materials, so it is expected that cyclic behavior will differ as well. However, the mechanisms that separate bulk from small-scale behavior are still not well understood. Only preliminary work has been performed in the area of cyclic loading of thin films [1,2].
Fatigue and Fracture Testing of Microelectromechanical Systems
Authors: Ballarini Roberto , Mullen Robert L. , Kahn Harold , Heuer Arthur H. 
Published: January 2022

Abstract
Polysilicon fracture mechanics specimens have been fabricated using standard MEMS (microelectromechanical systems) processing techniques, and as a result, have characteristic dimensions comparable to typical MEMS devices. These specimens are fully integrated with simultaneously fabricated electrostatic actuators which are capable of providing sufficient force to ensure catastrophic crack propagation from notches produced using micromachining. Thus, the entire fracture experiment takes place on-chip, without any possible influences from external sources. Fracture has been initiated using both monotonic and cyclic resonance loading. A typical device is shown in the figure below.
This talk will review the (1) design of the experiment, (2) fabrication procedure, (3) measurements of bending strength, critical energy release rate, and fatigue life under cyclic loading, and (4) changes being incorporated in the structural design to make the testing procedure more robust.
Cycle Based Modeling of Composite Fatigue
Authors: Dzenis Yuris A. 
Published: January 2022

Abstract
Fundamental relation between overall damage and failure process in laminates under cyclic loading and damage development within cycles is addressed. A general model for damage evolution and failure analysis of laminates under cyclic loading was developed based on the stochastic mesomechanics approach. The model combines lamination theory and a theory of excursions of random processes beyond the bounds. Randomness of elastic and strength properties of plies, laminate microstructure, and cyclic loading are taken into account. Capabilities of the model were illustrated by examples. The model was found capable of predicting three stages in the overall damage accumulation process, i.e. initial damage, gradual damage development, and final failure. Relative durations of these stages depended on load cycle parameters. Theoretical predictions were compared with acoustic emission observations of damage development in an unnotched graphite-epoxy laminate under low-cycle fatigue. Overall time history of acoustic emission was separated into emission during loading and unloading portions of the loading cycles. Histories of the locations of the AE sources and distributions of the acoustic events over the stress range were analyzed. It was concluded that most of the new damage was developed during the loading portions of the loading cycles. The emission during unloading was attributed to friction between crack faces. The time history of the new damage exhibited initial, steady, and final damage development stages. The new damage was developed over the entire stress range with higher damage rates at higher stress. Experimental observation corroborated with the results of theoretical analysis.
The Fracture Mechanics of Microelectromechanical Systems
Authors: Ballarini Roberto 
Published: January 2022

Abstract
A review of the state-of-the-art fracture mechanics of microelectromechanical systems (MEMS) is presented. Experimental data for fracture toughness, fatigue crack growth, and stress corrosion is critically reviewed, and recommendations are made for future research. A similar discussion is provided for theoretical fracture mechanics models.
Dimensional Stability of Composite in a Space Thermal Environment
Authors: Kim Ran Y. , Crasto Allan S. , Schoeppner Gregory A. 
Published: January 2022

Abstract
Composites are steadily replacing metals in weight-critical space structures primarily because of their high specific moduli. Many space structures require not only high stiffness but precision alignment and dimensional stability as well. These parameters are sensitive to thermal strains caused by the mismatch in coefficients of thermal expansion (CTE) of the constituents, anisotropy in ply CTE, and variations in service temperature. The CTE of a laminate can change in service as a result of mechanically or thermally induced microcracking and this may result in undesirable distortion of the composite structure.
In this work, changes in the CTE of a representative space structural material-XN-70/RS3 graphite/cyanate-ester were studied using strain gages. The longitudinal and transverse CTEs of unidirectional and crossply ([0/90]2s) laminates were initially determined over the temperature range of −157°C to 121°C. Specimens were then subjected to thermal cycles from −150°F to 250°F to induce microcracking. The specimen CTE was again measured in the same location after 25, 50, 100, 200, 500 and 1000 cycles, and the corresponding crack density (in the vicinity of the strain gage) was determined by microscopic examination of a polished specimen edge. Predictions of CTE variation with crack density were made using the axisymmetric formulation of a large-radius, hollow, layered-cylinder model, which is equivalent to the flat laminate formulation. The experimental results compared fairly well with the predictions for a [0/90]2s cross-ply laminate. This paper also includes a discussion of the statistical variation of the measured CTEs.
Analysis and Characterization of Interfacial Fracture Toughness in Model Composite
Authors: Tandon G. P. , Kim R. Y. 
Published: January 2022

Abstract
The aim of the present study is to evaluate interfacial fracture toughness in model polyester/epoxy composite. This composite system was recently studied by Tandon and Pagano [1] in a push-out test. The progressive debonding portion of the load-displacement response including initiation of debonding, propagation and eventually catastrophic debonding of the remainder of the bonded interface were predicted using a single parameter characterized as the critical shear energy release rate of the interface. The model [1] predicted the apparent toughness of the interface to increase with the length of the debond while the numerical contribution of shear stresses to the potential energy release rate was found to be nearly constant.
In this work, we have used the end-notch flexure specimen (0.5 inch thick) consisting of polyester and epoxy rectangular beams with a non-adhesive insert on the interface (mid plane) as a starter crack, to evaluate the Mode II fracture toughness. A three point bending fixture with a total span of 4 inches is installed in a load frame and tested in a displacement control mode. The Mode II fracture energy is calculated from the load-deflection curve and crack extension data using compliance calibration method. The end-notch flexure specimen is also analyzed using the large radius axisymmetric damage model by Schoeppner and Pagano [2]. It has been shown that in the limit as the ratio of average cylinder radius R to laminate thickness T approaches infinity, the stress components and the governing equations of the large radius model are analytically equivalent to the flat laminate formulation. The crack-closure method is then used to calculate the potential energy release rate and the analytical predictions are compared with the experimental data.
Micromechanical Modeling of Fiber Fragmentation in Single Fiber Composite Specimens
Authors: Davis Jean E. , Qu Jianmin 
Published: January 2022

Abstract
In this paper, a micromechanics model is developed to model the fiber fragmentation test using single fiber composite specimens (SFC). The SFC specimen considered here consists of a single brittle (SiC) fiber embedded in a ductile (Al) matrix. The goal is to predict the longitudinal constitutive behavior of the composite as damage occurs and to determine if the interfacial strength can be estimated from the fiber fragment length at a given effective strain.
Before the fiber fractures, the fiber-matrix interface is assumed perfect. During fiber fracture, the interface is damaged. An imperfect interface model is then employed. When the fiber fractures, the fragments are assumed to be uniformly distributed such that the fragment lengths are equal at each given load level. The Weibull strength distribution was used to relate the fiber fragment length to the tensile strength of the brittle fiber. An increase in the applied effective strain causes successive fractures in the fiber, in that the fragments become increasingly shorter. The length of the fiber fragments at a given level of effective strain is dependent upon the interfacial shear strength.
The finite element method was used to provide numerical solutions for the state of stress and fiber length at a given applied effective strain for each SFC, and to allow a better understanding of the interaction of each component. The numerical solutions were used to construct effective stress-strain curves showing the constitutive behavior and effective strain-fiber fragment length plots of each SFC modeled. Classical elasticity and mechanics of materials modeling techniques were also used to derive analytical solutions for the state of stress in each SFC. Approximate longitudinal stress-strain relationships were developed from these analytical solutions.
Guided Waves in a Fiber-Reinforced Composite Material With Interface Layers
Authors: Datta S. K. , Zhung W. , Shah A. H. 
Published: January 2022

Abstract
The mechanical response and failure of high-temperature fiber-reinforced materials are critically dependent on the mechanical properties of the interface (interphase) layers between the fibers and the matrix. Even though considerable amount of work has recently been done on the fracture of these materials, characterization of interface properties and their influence on deformation and failure is found to be a challenging problem. Guided ultrasonic waves provide a powerful tool to obtain the mechanical properties of the interface layers and the quality of the bond between the fiber and the matrix. In this paper, we present a model study of dispersion characteristics of both axisymmetric (n = 0) and nonaxisymmetric (n = 1) guided waves in a SiC fiber reinforced glass matrix. Here n stands for the circumferential wavenumber. It is assumed that the fiber has two surrounding layers separating it from the matrix: a thin layer of carbon and then a thin layer of TiB2. Surrounding matrix is a glass cylinder. Comparison of dispersion characteristics with and without the interface layers shows mode dispersion curves come very close at certain frequency-wavenumber values as if they cross. This phenomenon is often characterized as “pinching” and is found to be very sensitive to the interface (interphase) properties. Examination of the mode shapes at these points reveals mode interchanges. It is argued that careful study of the pinch effect can be used to obtain mechanical properties of the interface (interphase).
Sine Convolution Solution of the Integral Equation Form of Lamé’s Equations
Authors: Stenger Frank 
Published: January 2022

Abstract
We present here two integral equation formulations to the homogeneous Lamé equations(1.1)μ Δu+(λ+μ)∇ div u=0, as described in detail in [3]. In the final expanded paper of this abstract, we also shall present a detailed procedure for the approximate solution of these equations via Sinc convolution for the case of a region V that is a half space, as well as when V consists of two composite slabs in R3.
Effect of Deformation-Induced Change of Fiber Orientation on Nonlinear Behavior of Polymeric Composite Laminates
Authors: Sun C. T. , Zhu C. 
Published: January 2022

Abstract
Deformation can cause some change in fiber orientation in composite laminates. The purpose of this paper was to investigate the effect of such fiber orientation on the nonlinear behavior of polymeric composite laminates. Overstress viscoplasticity model was used to describe the rate-dependent nonlinear behavior of the composite lamina, and the laminate was modeled with the classical laminated plate theory. To verify the model, experiments were conducted on various laminate specimens of IM7/5260 and AS4/PEEK composites at different loading rates. The thermal residual stresses induced during curing were included using a simple thermoelasticity method. It was found that when curing stresses were not taken into consideration, the laminated plate theory would predict stiffer nonlinear responses than the data from the experimental results. For such laminates, the predictions with curing stresses are softer than without thermal stress, and usually good agreement between predictions and experiments can be reached. However, for some other laminates such as [±30°]ns, the predictions without curing stresses are too soft compared with the experimental data at relatively high strain level, and the consideration of curing stresses may make the predictions even worse. Moreover, such deviation between predictions and experiments cannot be remedied by considering possible damage or delamination in the laminates, since these factors will reduce the stiffness of the material. As a result, the theory will predict an even softer response if these factors are taken into account. It is clear that some other factors might be responsible for the deviation.
In this study, we found that the change of fiber orientation induced by deformation could play an important role in nonlinear stress-strain behavior. For angle ply laminates with θ greater than 45°, curing stresses are dominant in the behavior, and the change of fiber orientation has no effect. For θ lying between 20° and 40°, the curing stresses have a significant effect at low strain levels, while fiber orientation change has a greater effect at high strain levels.
Model to Predict the Effect of Through-Thickness Loading on Ply Cracking in General Symmetric Laminates
Authors: McCartney L. N. 
Published: January 2022

Abstract
For the case of the combined in-plane biaxial and shear loading of a general symmetric laminate having ply cracks in a single orientation, a stress transfer model has been developed that can predict the stress and displacement distributions at all points in the laminate provided that generalised plane strain conditions prevail, as expected in such laminates in regions away from free edges. For the special case of cross-ply laminates, the modelling of the effects of a uniform through-thickness loading has led to an extensive set of inter-relationships between the thermo-elastic constants, whose validity has been verified by solutions to the stress transfer model. These interrelationships have been used to develop a very simple crack formation criterion that involves a scalar effective stress that is able to take account of the general in-plane loading of the laminate. The paper will investigate the extension of these results to general symmetric laminates with ply cracks subject to a uniform through-thickness load combined with general in-plane loading involving both biaxial and shear stresses.
The paper will describe the assumptions on which the model is based, and the representation for the stress and displacement field that has been shown to be consistent with the Reissner variational principle whose application to composites has been pioneered by Pagano. Following Pagano, ply refinement techniques will be used to improve the accuracy of predictions, and indicate the nature of the singularity that exists at the tips of the ply cracks. The model will be used to predict the dependence of the thermoelastic constants on crack density, and to investigate the validity of new inter-relationships between the predicted constants. The inter-relationships will be used to develop a relatively simple crack formation criterion that generalises the known cross-ply criterion to the important case of general symmetric laminates.
Evidence will be presented showing how the new model has been validated by comparison of predictions with finite element analysis for cracked laminates (e.g. quasi-isotropic laminates), and with experimental data.