bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fiber Pullout Characteristics Under Dynamic Loading Conditions
Authors: Sridhar N. , Yang Q. D. , Cox B. N. 
Published: November 2021

Abstract
Inertial effects in the mechanism of fiber pullout during dynamic propagation of a bridged crack are critically examined. By reposing simple shear lag models of pullout as problems of dynamic wave propagation, the effect of frictional coupling between the fiber and the matrix is accounted for in a fairly straightforward way. The frictional sliding between the fiber and the matrix is described by a constant interfacial friction stress, the sign of which depends on the relative particle velocity of the fiber and the matrix. Analytical solutions are derived when the load or bridging traction on the fiber in the crack plane increases linearly in time. The results show that when the wave speed of the matrix exceeds a critical value, the frictional fiber pullout behavior transitions from a state of pure slip to a state where part of the sliding zone slips and the remaining sticks. When stick occurs, the fiber and the matrix within the stick zone slide past each other with an interfacial shear stress less than the shear stress required for slipping. Regions of slip and stick propagate and increase with time and influence the time-dependent relationship between the crack opening displacement and the bridging tractions.
Bending Failure Behavior of Recycled Aluminum Reinforced Composites
Authors: June Brian M. , Pidaparti Ramana M. , El-Mounayri Hazim 
Published: November 2021

Abstract
In order to effectively use the recycled aluminum cans, many applications of aluminum are being explored. One of the most obvious applications is to reinforce with wood or others, to form sandwich composites. The goal of the proposed work is to conduct the research to develop constructional products, which would permit reuse of aluminum cans instead of destroying the structure by melting or trashing. With that goal in mind, our specific objective of this study is to evaluate the stiffness and failure behavior of recycled aluminum reinforced composites under three-point bending for use in composite industries. Composite specimens containing the end sections of the can sandwiched between top and bottom layers of wood are investigated. The results of bending stiffness and failure behavior of sandwich composite panels obtained from the three-point bending tests are presented and discussed.
Design Study of Composite Sandwich Truck Tank Using a High-Order Sandwich Theory Approach
Authors: Thomsen Ole T. , Vinson Jack R. 
Published: November 2021

Abstract
The paper presents a preliminary design study on the structural response of a boxy composite sandwich truck tank subjected to hydraulic head loading. The design study is approximate in that it considers a 2-D cross section of the composite sandwich truck tank. The design study is performed using a high-order sandwich theory formulation in which the elastic responses of the face laminates are accounted for individually, and in which the transverse flexibility of the sandwich core is included. Thus the model allows the sandwich panel thickness of the truck tank to change during deformation, and the model accounts for the existence of transverse normal stresses in the core material in the sandwich panel sections. The paper includes a presentation of the high-order formulation for the curved sandwich panel parts of the composite sandwich truck tank sections, as well as a brief description of the numerical solution of the complete set of system equations with corresponding boundary conditions. The paper is concluded with a numerical study, showing the characteristic features of the elastic response of a composite sandwich truck tank section subjected to hydraulic head loading.
Dynamic Response of Sandwich Anisotropic Flat Panels to Explosive Pressure Pulses
Authors: Hause Terry , Librescu Liviu 
Published: November 2021

Abstract
This paper addresses the problem of the dynamic response in bending of flat sandwich panels exposed to time-dependent external pulses. The study is carried out in the context of an advanced model of sandwich structures that is characterized by anisotropic laminated face sheets and an orthotropic core layer. A detailed analysis of the influence of a large number of parameters associated with the particular type of pressure pulses, panel geometry, fiber orientation in the face sheets and, presence of tensile uni/biaxial edge loads is accomplished, and pertinent conclusions are outlined.
Free Vibration of High-Order Curved Sandwich Beams
Authors: Frostig Yeoshua , Bozhevolnaya Elena 
Published: November 2021

Abstract
A high-order model for free vibrations of singly curved sandwich beams is presented. The model takes into account the transverse flexibility of the sandwich core while the faces of the sandwich are treated as thin beams. Linear equations of motion as well as the natural boundary conditions are derived. It is shown for the curved sandwich beams, that there exist four eigen modes. A numerical analysis of free vibration of the simply supported beams is carried out. Effects of design parameters of the sandwich constituents on the eigen modes and their appropriate frequencies are investigated.
Suddenly Arrested Intersonic Shear Crack
Authors: Huang Y. , Gao H. 
Published: November 2021

Abstract
We study a mode II crack suddenly stopping after propagating intersonically for a short time. The solution is obtained by superposing the fundamental solution and the auxiliary problem of a static crack emitting dynamic dislocations such that the relative crack face displacement in the fundamental solution is negated ahead of where the crack tip has stopped. We find that, after the crack stops moving, the stress intensity factor rapidly rises to a finite value and then starts to change gradually toward the equilibrium value for a static crack. A most interesting feature is that the static value of stress intensity is reached neither instantaneously like a suddenly stopping subsonic crack nor asymptotically like a suddenly stopping edge dislocation. Rather, the dynamic stress intensity factor changes continuously as the shear and Rayleigh waves catch up with the stopped crack tip from behind, approaches negative infinity when the Rayleigh wave arrives, and then suddenly assumes the equilibrium static value when all the waves have passed by. This study is an important step toward the study of intersonic crack propagation with arbitrary, non-uniform velocities.
High Strain Rate Response of PVC Foams
Authors: Thomas Tonnia , Mahfuz Hassan , Carlsson Leif A. , Kanny Krishnan , Jeelani Shaik 
Published: November 2021

Abstract
In this study, cross-linked poly-vinylchloride (PVC) closed-cell foams were examined under high strain rate compression loading using a servohydraulic testing machine and a modified Split Hopkinson Pressure Bar (SHPB) apparatus with a steel incident bar and a polycarbonate transmitter bar for strain rates up to 2000 s−1. Three foam densities were examined, viz. 75, 130, and 260 kg/m3.
The stress and strain-time history and stress-strain behavior were evaluated. An increase of stress and strain was observed for all categories of foam as strain rate increased. A post impact study was also performed to evaluate the failure modes of the foam cores. A densification band of collapsed cells was the major mode of failure.
Size Effect in Fracture of Sandwich Structure Components: Foam and Laminate
Authors: Bažant Zdeněk P. , Zhou Yong , Novák Drahomír , Daniel Isaac M. 
Published: November 2021

Abstract
In the design of sandwich plates and shells for very large structures, such as ships in the range of 100 m length, it is very important to take the size effect on the nominal strength into account, and do so in a realistic, physically justified, manner. Before the size effect is addressed for a sandwich structure, it must be understood for its components — the foam core and the laminate skins. In the current practice, the size effects are automatically attributed to the randomness of material strength, as described by the Weibull theory. The purpose of this paper is to show that in both the foam and the laminate there are deterministic size effects, which are generally more pronounced. They are caused by stress redistribution and energy release due to the growth of large fractures or large cracking zones prior to attaining the maximum load. This deterministic size effect is verified and calibrated by new tests of notched specimens of rigid close-cell vinyl foam. A combined deterministic-probabilistic theory of size effect of the laminates is proposed and verified by extensive test data.
Derived Interaction Parameters for the TSAI-WU Tensor Polynomial Theory of Strength for Composite Materials
Authors: DeTeresa Steven J. , Larsen Gregory J. 
Published: November 2021

Abstract
It is shown that the two interactive strength parameters in the Tsai-Wu tensor polynomial strength criterion for fiber composites can be derived in terms of the uniaxial or non-interacting strength parameters if the composite does not fail under practical levels of hydrostatic pressure or equal transverse compression. Thus the required number of parameters is reduced from seven to five and all five of the remaining strength terms are easily determined using standard test methods. The derived interactive parameters fall within the stability limits of the theory, yet they lead to open failure surfaces in the compressive stress quadrant. The assumptions used to derive the interactive parameters were supported by measurements for the effect of hydrostatic pressure and unequal transverse compression on the behavior of a typical carbon fiber composite.
Evolution of Interfacial Decohesion in Particulate Composites
Authors: Dvorak George J. , Zhang Jian 
Published: November 2021

Abstract
Evolution of distributed damage in heterogeneous solids is modeled using the Transformation Field Analysis method [Proc. R. Soc. Lond. A (1992) 437, 311–327] and selected models of interface debonding in fibrous or particulate composites, as described in detail in the forthcoming paper [J. Mech. Phys. Solids Boehler Memorial Volume, 2001]. In this approach, stress changes caused by local debonding under increasing overall loads are represented by residual stresses generated by damage-equivalent eigenstrains that act together with the applied mechanical loading program and physically based local transformation strains on an undamaged elastic aggregate. Damage rates are derived from a prescribed probability distribution of interface strength and local energy released by debonding. Numerical simulations of damage evolution in a glass/elastomer composite indicate which of these two conditions controls the process at different reinforcement densities and overall stress states. In general, the energy released by a single particle at given overall stress decreases with increasing reinforcement density, and in proportion to particle size. Therefore, dense reinforcement by smaller-diameter particles or fibers should enhance damage resistance of composite systems.
The High Velocity Impact Response of Novel Fiber Metal Laminates
Authors: Cantwell Wesley J. , Wade Graham , Guillen J. Fernando , Reyes-Villanueva German , Jones Norman , Compston Paul 
Published: November 2021

Abstract
The impact resistance of a range of novel fiber metal laminates based on polypropylene, polyamide and polyetherimide matrices has been investigated. Initial attention focused on optimizing the interface between the composite and aluminum alloy constituents. Here, it was shown that composite-metal adhesion was excellent in all systems examined. In addition, tests at crosshead displacement rates up to 3 m/s indicated that the interfacial fracture energies remained high under dynamic loading conditions.
High velocity impact tests on a series of 3/2 laminates (3 layers of aluminum/2 layers of composite) highlighted the outstanding impact resistance of a number of these systems. The glass fiber reinforced polypropylene system offered a particularly high impact resistance exhibiting a perforation energy of approximately 160 Joules. Here, failure mechanisms such as extensive plastic drawing in the aluminum layers and fiber fracture in the composite plies were found to contribute to the excellent energy-absorbing characteristics of these systems.
Dynamic Mechanical Properties of Fiber-Metal Laminates
Authors: Liu Jianjun , Liaw Benjamin , Pamwar Manish 
Published: November 2021

Abstract
Fiber-metal laminated cantilever beams, made of glass-fiber reinforced GLARE and aramid-fiber reinforced ARALL laminates interlaced with aluminum layers, were first excited by a shaker at various frequencies surrounding resonances. Dynamic Young’s moduli and damping ratios were then evaluated using both free-vibration (resonance) and forced-vibration (non-resonance) schemes. Results from both schemes are in good agreement. Compared to aluminum alloys, the dynamic Young’s moduli of fiber-metal laminates are relatively lower. For all types of fiber-metal laminates tested in this study, their values are almost constant within an excitation frequency range up to 5,000 Hz whereas the damping ratios oscillate within a narrow range of 0 to 0.02. The obtained dynamic moduli are in excellent agreement with their static counterparts. Better results were obtained when using a strain gage near the clamped end, as compared to a piezoelectric accelerometer at the tip.
Crashing Behavior of Braided Composites
Authors: Hamada Hiroyuki 
Published: November 2021

Abstract
FRP exhibits not only the excellent strength to weight than conventional metallic materials, but also high energy absorption properties. Therefore FRP would be applied to structural components for various vehicles recently. Particularly, braided composites are expected to utilize for safety components, because they show the fracture mode called progressive crushing, which proceeds under constant load. Energy absorption with progressive crushing was generated by combination of fiber fracture, delamination, crack, etc. In this paper, the crushing properties, especially fracture mechanisms of FRP rods were investigated. To discuss the fracture morphology, microscopic observations were examined.
Studies on Headform Impact Design
Authors: Deb Anindya 
Published: November 2021

Abstract
HIC(d) (Head Injury Criterion, dummy) is defined as a kinematic relationship involving resultant translational deceleration at the CG (center of gravity) of a biofidelic headform and duration of contact. As deceleration response of a headform is in general a function of the energy-absorbing and geometrical properties of an obstructing structure (for a given impact speed), HIC(d) can be expressed, at least symbolically, as a function of those properties. The current paper uses a simplified mathematical model to capture the worst case of headform impact as considered in the FMVSS 201 regulation for upper interior head impact. The obstructing structural countermeasure in the path of a colliding headform is assumed to possess idealized elastoplastic although physically relevant behavior under loading. During the process of designing for headform impact safety compliance, which often turns out to be a trial-and-error process, it is sometimes difficult to see the correspondence between HIC(d) and the relative effectiveness of design iterations in terms of energy-absorption. Thus, relationship between HIC(d) and energy absorbed by such structural countermeasures is investigated. Based on results obtained from the current model and a new approach, an explicit relationship is derived between HIC(d) and the characteristic properties of an energy-absorbing countermeasure that can be used as a design aid.
Frontal Impact Test and Analysis on an Aluminum Front-End Structure
Authors: Caliskan Ari G. , Koganti Rama 
Published: November 2021

Abstract
A frontal impact test was performed on a front-end module consisting of 6xxx series aluminum extrusions, and some 5xxx series aluminum stampings as reinforcements. The front end structure consists mainly of a bumper, cross member, radiator support, front and backup lower rails, upper rails, and shock tower support. In addition to the main structure, a subframe containing the engine was also attached to the back-up rails. The front-end module was mounted on a sled at the upper and lower A-pillar points as well as at the back-up rail. In addition to measuring the barrier forces, load cells were located behind the main structural members to determine load transfer. The results of the tests showed progressive folding of the crush rails, and adequate absorption of the impact energy. To aid in the design, a CAE model of the front-end was created to determine the crash behavior of the structure during frontal impact. The final model, which took into account, the material properties of the weld joints showed good agreement with test results.
Global Characterization of Failure Modes Under Impact Loading in Structural Components Made of Low Ductility Materials
Authors: Wu Shen Rong , Chen Xiaoming , Hu Weiran 
Published: November 2021

Abstract
This study reviews the impact failure modes of structural components made of materials with low ductility such as aluminum and magnesium. Tensile failure is observed at large stretch area or on the tension side of large bending deformation. Material breakage due to shear may also occur. There are several approaches to simulate the material failure process in explicit finite element software used for crashworthiness analysis. Evaluation of the effective applications of these material models is presented with a finite element simulation of bi-axial loading tests. The forming limit diagram is used to evaluate various failure criteria. Component crash simulations are presented to demonstrate the applications of failure criteria.
Evaluation of Rear Impact Seat System Performance Using a Combined Load Neck Injury Criteria and Hybrid III Surrogates
Authors: Saczalski Kenneth J. , Burton Joseph Lawson , Lewis Paul R. , Saczalski Todd K. , Baray Peter E. 
Published: November 2021

Abstract
Vehicle to vehicle rear impact crash tests and sled buck tests were run to evaluate seat system performance related to Hybrid III surrogate response and comparison with NHTSA proposed combined load injury assessment values, as well as standard injury criteria. The crash and sled buck test impact conditions were modeled after actual case study incidents where changes in the rear impacted vehicle speeds ranged from about 25 to 50 kph. With the exception of one baseline vehicle-to-vehicle rear impact test, the dynamic tests provided side-by-side comparisons, and test-to-test evaluations, of surrogate response in conventional yielding front seats versus much stronger seat systems such as the belt integrated seat designs. Head, neck and chest injury criteria were used in the evaluations, including both the proposed NHTSA combined load neck criteria and SAE J 885 injury values. The surrogate response injury levels for the conventional yielding seats correlated well with the actual case study injury results. The seat comparison response generally indicated much reduced head and neck injury potential to surrogates seated in the stronger seat designs. The dynamic tests also demonstrate the importance of testing within the full vehicle interior structure to insure that floor strength is compatible with seat strength, so as to attain optimum occupant protection in stronger seat designs, and to assess injury risk to occupants in yielding or collapsing seat designs, as well as rear seated occupants, such as children. The tests indicate that quasi-static seat strength measurements made with more realistic “torso body block” load devices can provide reasonable estimates on the ultimate failure modes and dynamic load capabilities of the seat systems if the seat systems are properly mounted to the vehicle. Quasi-static seat strength results are presented for a variety of conventional collapsing seat designs and stronger seat systems like the belt integrated designs. One sled buck test was run with a rear-seated child surrogate to demonstrate the hazard of front seat collapse into the rear seat occupant area. The results of these tests further demonstrate the need for dynamic testing to assess total seat system performance and full occupant protection in rear impacts.
The Development and Validation of a Finite Element Human Thorax Model for Automotive Impact Injury Studies
Authors: Chang Fred 
Published: November 2021

Abstract
Computational simulations are becoming more important in automotive safety engineering. To simulate the occupants during the crash environment, dummies are currently used to represent the occupants. However, current dummies and dummy models lack the detailed information to predict the occupant injuries during a crash. And for the human thorax models, simplified geometry and non strain-rate material properties were used for the rib cage with no ability to simulate the rib fractures often seen in an automotive crash. Therefore, a detailed finite element human thorax model with proper material properties and the capability to simulate the rib fractures is needed to better understand the thoracic injuries under frontal and side impacts.
The current thorax model, based on a previous skeleton model with heart and lung by Deng et al. [1]. used digital surface images to construct the three-dimensional finite element representation of the spine, rib cage, arms, surface muscles, heart, lungs, and major blood vessels. Strain-rate-dependent properties were utilized for the rib cage. With the rib fracture prediction, the model showed good correlation with the test results.
Extended Occupant Safety Through Virtual Testing: Objectives of the European Project VITES
Authors: van Hoof Jack , Happee Riender , Puppini Roberto , Baldauf Hans , Oakley Charles 
Published: November 2021

Abstract
Increasingly stringent international passenger safety norms and the need to reduce vehicle body weight for environmental and protection requirements demand efficient and innovative design methods. Computer simulation, or virtual testing, allows an integrated evaluation of these aspects in the early design stages and thereby reduces costs for prototyping and reduces time-to-market. This paper deals with the application of virtual testing in vehicle passive safety design to:
(1) reduce injury numbers by enhancing passive safety for a wide range of conditions, and
(2) reduce the duration and costs of the vehicle design by improving the efficiency of the design process.
A validated virtual test procedure will be developed to extend the range of protection beyond current regulations to real life crash conditions. This will be achieved by 1) developing procedures and guidelines to standardise numerical models and simulations; 2) accounting for the experimentally observed scatter in simulations by stochastic modelling; and 3) identify gaps in current regulations where occupants are not optimally protected. All steps needed for acceptance of this virtual test procedure in regulations or in a consumer test method will be taken into account.