scholarly journals High-Strain-Rate Compressive Behavior of UHMWPE Fiber Laminate

2020 ◽  
Vol 10 (4) ◽  
pp. 1505 ◽  
Author(s):  
Yihui Zhu ◽  
Xiaoyun Zhang ◽  
Benyuan Xue ◽  
Hengsha Liu ◽  
Yaoke Wen ◽  
...  
Keyword(s):  
Strain Rate ◽  
Fracture Stress ◽  
Maximum Stress ◽  
Dynamic Testing ◽  
Numerical Models ◽  
Test Machine ◽  
Stress Strain ◽  
Uhmwpe Fiber ◽  
Out Of Plane ◽  
Plane Direction

Ultra-high-molecular-weight polyethylene (UHMWPE) fiber laminate is currently widely used in ballistic protection for its exceptional physical and mechanical properties. However, the dynamic compressive mechanism of UHMWPE laminate remains poorly understood. Therefore, the stress–strain relationship, the influence of different thickness, area, and shape, and the maximum stress and fracture stress are studied in both out-of-plane and in-plane directions under quasi-static and dynamic loading using a universal test machine, Split Hopkinson pressure bar (SHPB), and high-speed camera. Furthermore, numerical models with cohesive elements are developed. The results indicate a dependency on strain rate and loading direction. Firstly, the stress–strain curve of dynamic testing can be divided into different zones according to different loading directions and strain rates. Secondly, with the increase of the strain rate in the dynamic testing, the maximum stress and fracture stress increase as well; relatively speaking, the fracture stress in the out-of-plane direction is greater than the fracture stress in the in-plane direction. Thirdly, both experiment and simulation indicate that the thickness does not influence the modulus clearly the in out-of-plane direction but influences the modulus in the in-plane direction. Fourthly, the fracture stress of dynamic testing is higher than the fracture stress of quasi-static testing in both directions. Finally, the numerical results show good agreement with the experiment in terms of the maximum stress and failure form.

On the Determination of Stress, Strain, Strain-Rate Relations From Dynamic Beam Tests

1969 ◽  
Vol 36 (3) ◽  
pp. 632-634 ◽  
Author(s):  
P. P. Gillis ◽  
J. M. Kelly
Keyword(s):  
Strain Rate ◽  
Dynamic Testing ◽  
Direct Method ◽  
Bending Moment ◽  
Experimental Results ◽  
Stress Strain ◽  
Analytical Technique ◽  
Flexural Response ◽  
Flexural Tests

A direct method is proposed for the determination of stress, strain, strain-rate relations from dynamic flexural tests in which bending moment is given in terms of curvature and curvature rate, or any other suitable deformation parameter and deformation rate parameter. The method is demonstrated by application to published experimental results. It is found that the stress, strain, strain-rate relations that are derived from the flexural test data are in significantly better accord with uniaxial data on the same material, than moment, curvature, curvature-rate relations predicted from the uniaxial data correspond with the experimental results. It appears that the process of reducing flexural data to uniaxial relations by the method proposed is much less sensitive than that of predicting flexural response from uniaxial data. Since flexural tests have many experimental advantages over uniaxial tests this analytical technique seems to open up possibilities for improved dynamic testing methods.

scholarly journals Mechanical properties of high-density TRIP steel honeycomb structures with varying cell profiles under different loading conditions

2018 ◽  
Vol 183 ◽  
pp. 03014 ◽  
Author(s):  
Christine Baumgart ◽  
Christian Weigelt ◽  
Christos G. Aneziris ◽  
Lutz Krüger
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Compression ◽  
Wall Material ◽  
Cell Geometry ◽  
Channel Axis ◽  
Honeycomb Structures ◽  
Loading Direction ◽  
Out Of Plane ◽  
Plane Direction

As the mechanical properties of honeycomb structures are influenced by several parameters, detailed analysis is necessary before their potential application in transportation industry components. Previous Finite Element Model (FEM)-based numerical analysis demonstrated that variation in cell geometry affects the achievable strength level and, thus, the energy absorption capability. According to this FEM study, the Kagome geometry – an ordered sequence of hexagons and triangles – exhibits properties that are particularly promising when compared to the square-celled structures investigated to date. When the load is applied parallel to the channel axis (the out-of-plane direction), the increment of strength is comparatively low, whereas in the in-plane direction (loading orthogonal to the channel axis), the dissipated specific energy can reach almost double that of the square-celled structure. In this study, the results of static and dynamic compression tests – performed in the out-of-plane and in-plane modes – are presented to examine the influence of strain rate and loading direction on the characteristic deformation stages of squarecelled and Kagome structures. Particular attention is paid to deformation induced martensite formation in the cell wall material, indicating the TRansformation Induced Plasticity (TRIP) effect as a function of applied cell geometry, strain rate and loading direction.

Dynamic Response of Symmetric and Asymmetric E-Glass / Epoxy Laminates at High Strain Rates

2010 ◽  
Vol 446 ◽  
pp. 73-82 ◽  
Author(s):  
Mostapha Tarfaoui ◽  
S. Choukri ◽  
A. Neme
Keyword(s):  
Maximum Stress ◽  
Failure Modes ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
High Speed Photography ◽  
Strain Rates ◽  
High Strain Rates ◽  
Stress Strain ◽  
Out Of Plane

The mechanical properties of E-glass/epoxy composite at high strain rates are important in evaluating this kind of composite under dynamic and impulsive loading. The in-plane and out-of-plane compressive properties at strain rates from 300 to 2500 s-1 were tested with split Hopkinson pressure bar. Samples were tested in the thickness as well as in-plane direction for seven fibre orientations: 0°, 20°, 30°, 45°, 60°, 70° and 90°. The kinetics of damage and the failure modes were identified using a high-speed photography, infrared camera, optical techniques and a scanning electron microscope. Results of the study were analyzed in terms of maximum stress, Strain at maximum stress, failure modes, damage history and fibres orientation effects. From the experimental data, the stress-strain curves, compressive stiffness, and compressive strain of the composite are rate-sensitive in in-plane and out-of-plane compressive directions. The failure and damage mechanisms are implicitly related to the rise in temperature during static and dynamic compression.

Stress-Strain Behaviour of Dielectric Elastomer for Actuators

2015 ◽  
Vol 789-790 ◽  
pp. 837-841 ◽  
Author(s):  
R.K. Sahu ◽  
K. Patra ◽  
S. Bhaumik ◽  
A.K. Pandey ◽  
D.K. Setua
Keyword(s):  
Strain Rate ◽  
Maximum Stress ◽  
Dielectric Elastomer ◽  
Cyclic Softening ◽  
Hysteresis Loss ◽  
Commercial Application ◽  
Stress Strain ◽  
Rate Dependent ◽  
Nonlinear Stress ◽  
Loading Case

Dielectric elastomer (DE) is gaining importance for potential strategic and commercial application as actuators. This paper reports the experimental investigation on different mechanical phenomena at large deformation of a commercially available acrylic dielectric elastomer material, VHB 4910 (3M) which is widely used for dielectric elastomer actuator (DEA) research. Attempts are made for accurate and precise experimental determination of nonlinear stress-strain, strain rate dependent hysteresis behaviour and cyclic softening of this material. It is observed that with the increase in strain rate maximum stress at a particular strain increases whereas hysteresis loss decreases. In the cyclic loading case after a particular number of cycles almost the hysteresis loss and maximum stress becomes constant. These experimental results are likely to be interesting for the designers for proper designing and characterization of the actuators fabricated with this material.

scholarly journals Impact Testing of Stainless Steel Materials

2005 ◽  
Author(s):  
R. K. Blandford ◽  
D. K. Morton ◽  
T. E. Rahl ◽  
S. D. Snow
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Impact Test ◽  
Spent Nuclear Fuel ◽  
Impact Testing ◽  
Radioactive Material ◽  
Test Machine ◽  
Strain Rates ◽  
Stress Strain ◽  
The Impact

Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates (10 to 200 per second) during accidental drop events. Mechanical characteristics of these materials under dynamic (impact) loads in the strain rate range of concern are not well documented. The goal of the work presented in this paper was to improve understanding of moderate strain rate phenomena on these materials. Utilizing a drop-weight impact test machine and relatively large test specimens (1/2-inch thick), initial test efforts focused on the tensile behavior of specific stainless steel materials during impact loading. Impact tests of 304L and 316L stainless steel test specimens at two different strain rates, 25 per second (304L and 316L material) and 50 per second (304L material) were performed for comparison to their quasi-static tensile test properties. Elevated strain rate stress-strain curves for the two materials were determined using the impact test machine and a “total impact energy” approach. This approach considered the deformation energy required to strain the specimens at a given strain rate. The material data developed was then utilized in analytical simulations to validate the final elevated stress-strain curves. The procedures used during testing and the results obtained are described in this paper.

Compressive Response of UHMWPE/Vinyl Ester 3D Orthogonal Woven Composites at High Strain Rates

2010 ◽  
Vol 97-101 ◽  
pp. 522-525 ◽  
Author(s):  
Ying Sun ◽  
Guo Jun Wang
Keyword(s):  
Strain Rate ◽  
Yield Stress ◽  
Dynamic Loading ◽  
Vinyl Ester ◽  
High Strain ◽  
Woven Composites ◽  
Strain Rates ◽  
Stress Strain ◽  
Uhmwpe Fiber ◽  
3D Orthogonal Woven

The high strain rate compressive properties of UHMWPE/ vinyl ester 3D orthogonal woven composites are investigated experimentally. The composites are made from UHMWPE fiber 3D orthogonal woven preforms impregnated with vinyl ester resin by resin transfer molding. The samples are subjected to dynamic loading through the thickness direction using the Split Hopkinson Pressure Bar at three kinds of strain rate. The testing results are compared with the results of quasi-static tests on specimens with the same fiber volume fraction. The stress-strain relationships of UHMWPE/vinyl ester 3D orthogonal woven composites are rate dependent. It is found that the yield stress, strain at yield stress and modulus increased with the increased the strain rates. Additionally, the predominant failure mode of the composites under dynamic loading shear fracture from the optical microscopic images of fracture surfaces.

Dynamic out-of-plane compressive failure mechanism of C/C composite: Strain rate effect on the defect propagation and microstructure failure

2021 ◽  
pp. 1-31
Author(s):  
Fei Guo ◽  
Qingguo Fei ◽  
Yanbin Li ◽  
Nikhil Gupta
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Failure Mechanism ◽  
Maximum Stress ◽  
Testing Machine ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Compressive Failure ◽  
Macro Scale ◽  
Out Of Plane

Abstract Out-of-plane compression experiments with the strain rate from 0.0001/s to 1000/s are performed on 3D fine weave pierced Carbon/Carbon (C/C) composite using a universal testing machine, a high-speed testing machine, and a split Hopkinson pressure bar (SHPB). The compressive failure mechanism of the composite is analyzed by multi-scale analysis method, which ranges from micro-scale defect propagation, through meso-scale microstructure failure, to macro-scale material failure. In order to predict the out-of-plane compressive properties of 3D fine weave pierced C/C composite at different strain rates, a strain-rate-dependent compressive constitutive model is proposed. The results show that the out-of-plane compressive behavior of the 3D fine weave pierced C/C composite is sensitive to strain rate. With increasing the strain rate, the initial compressive modulus, the maximum stress and the strain at the maximum stress increase. The difference in mechanical behavior between quasi-static and high strain rate compression is owing to the strain rate effect on the defect propagation of the 3D fine weave pierced C/C composite. The proposed constitutive model matches well with the experimental data.

Research on Flow Behavior of Advanced High Strength Steel at Elevated Temperature

2013 ◽  
Vol 749 ◽  
pp. 498-503
Author(s):  
Cheng Xi Lei ◽  
Jun Jia Cui ◽  
Zhong Wen Xing ◽  
Hao Zhao
Keyword(s):  
Strain Rate ◽  
Linear Equation ◽  
High Strength Steel ◽  
Elevated Temperatures ◽  
Flow Behavior ◽  
Peak Stress ◽  
High Strength ◽  
Test Machine ◽  
Advanced High Strength Steel ◽  
Stress Strain

Tensile experiments were carried out on advanced high strength steel (AHSS) by the test machine Gleeble3500, under the temperature ranging from 650 to 850 and the strain rate of 0.1/s~5/s, and the corresponding stress-strain curves were obtained. The peak stress level decreases with the increasing of deformation temperature or the decreasing of strain rate, which can be represented by a ZenerHollomon parameter in a linear equation. A revised model describing the relationships between the peak stress, strain rate and temperature of advanced high strength steel at elevated temperatures was proposed by compensation of strain and strain rate. The comparison of the predicted and experimental results of stressstrain curve can prove the good predictive power of the model, the Adj. R-Square between the peak stress and the linear equation was reached to 0.97.

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