High Strain-Rate Compressive Characteristics of Carbon/Epoxy Laminated Composites in Through-Thickness Direction

2004 ◽  
Vol 1-2 ◽  
pp. 11-16 ◽  
Author(s):  
Takashi Yokoyama
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Laminated Composites ◽  
Fiber Direction ◽  
Strain Rates ◽  
Thickness Direction ◽  
Hopkinson Pressure Bar ◽  
Total Strain Energy ◽  
Split Hopkinson ◽  
Pressure Bar

Compressive stress-strain characteristics of carbon/epoxy laminated composites in the through-thickness direction at strain rates of over 1000/s were evaluated using the standard split Hopkinson pressure bar. Three carbon/epoxy laminated composites (i.e., unidirectional, cross-ply and woven) with almost the same thickness were tested at room temperature. Small solid cylindrical specimens were machined such that the direction of the compression loading was perpendicular to the fiber direction of the laminates. The effects of strain rate and reinforcement geometry on the secant modulus at 1% strain, ultimate compressive strength and strain, and total strain energy to failure were examined in detail.

scholarly journals Study on the dynamic properties of AM-SLM AlSi10Mg alloy using the Split Hopkinson Pressure Bar (SHPB) technique

2018 ◽  
Vol 183 ◽  
pp. 04005 ◽  
Author(s):  
Bar Nurel ◽  
Moshe Nahmany ◽  
Adin Stern ◽  
Nahum Frage ◽  
Oren Sadot
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Static Mechanical ◽  
Split Hopkinson ◽  
Pressure Bar

Additive manufacturing by Selective Laser Melting of metals is attracting substantial attention, due to its advantages, such as short-time production of customized structures. This technique is useful for building complex components using a metallic pre-alloyed powder. One of the most used materials in AMSLM is AlSi10Mg powder. Additively manufactured AlSi10Mg may be used as a structural material and it static mechanical properties were widely investigated. Properties in the strain rates of 5×102–1.6×103 s-1 and at higher strain rates of 5×103 –105 s-1 have been also reported. The aim of this study is investigation of dynamic properties in the 7×102–8×103 s-1 strain rate range, using the split Hopkinson pressure bar technique. It was found that the dynamic properties at strain-rates of 1×103–3×103 s-1 depend on a build direction and affected by heat treatment. At higher and lower strain-rates the effect of build direction is limited. The anisotropic nature of the material was determined by the ellipticity of samples after the SHPB test. No strain rate sensitivity was observed.

Studies on the Dynamic Compressive Properties of Open-Celled Aluminum Alloy Foams

2006 ◽  
Vol 306-308 ◽  
pp. 905-910 ◽  
Author(s):  
Zhi Hua Wang ◽  
Hong Wei Ma ◽  
Long Mao Zhao ◽  
Gui Tong Yang
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Aluminum Foams ◽  
Wide Range ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Dynamic Loading Conditions

The compressive deformation behavior of open-cell aluminum foams with different densities and morphologies was assessed under quasi-static and dynamic loading conditions. High strain rate experiments were conducted using a split Hopkinson pressure bar technique at strain rates ranging from 500 to 1 2000 − s . The experimental results shown that the compressive stress-strain curves of aluminum foams also have the “ three regions” character appeared in general foam materials, namely elastic region, collapse region and densification regions. It is found that density is the primary variable characterizing the modulus and yield strength of foams and the cell appears to have a negligible effect on the strength of foams. It also is found that yield strength and energy absorption is almost insensitive to strain rate and deformation is spatially uniform for the open-celled aluminum foams, over a wide range of strain rates.

Measurement of Mechanical Properties of St 37 Material at High Strain Rates Using a Split Hopkinson Pressure Bar

2014 ◽  
Vol 660 ◽  
pp. 562-566 ◽  
Author(s):  
Akbar Afdhal ◽  
Leonardo Gunawan ◽  
Sigit P. Santosa ◽  
Ichsan Setya Putra ◽  
Hoon Huh
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Test Specimen ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Split Hopkinson ◽  
Pressure Bar

The dynamic mechanical properties of a material are important keys to investigate the impact characteristic of a structure such as a crash box. For some materials, the stress-strain relationships at high strain rate loadings are different than that at the static condition. These mechanical properties depend on the strain rate of the loadings, and hence an appropriate testing technique is required to measure them. To measure the mechanical properties of a material at high strain rates, ranging from 500 s-1 to 10000 s-1, a Split Hopkinson Pressure Bar is commonly used. In the measurements, strain pulses are generated in the bars system, and pulses being reflected and transmitted by a test specimen in the bar system are measured. The stress-strain curves as the material properties of the test specimen are obtained by processing the measured reflected and transmitted pulses. This paper presents the measurements of the mechanical properties of St 37 mild steel at several strain rates using a Split Hopkinson Pressure Bar. The stress-strain curves obtained in the measurement were curve fitted using the Power Law. The results show that the strength of St 37 material increases as the strain rate increases.

Experimental Research on Dynamic Mechanical Properties of 5083 Aluminum Alloy

2013 ◽  
Vol 535-536 ◽  
pp. 497-500 ◽  
Author(s):  
Zhi Wu Zhu ◽  
Guo Zheng Kang ◽  
Dong Ruan ◽  
Yue Ma ◽  
Guo Xing Lu
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
High Strength ◽  
Dynamic Mechanical Properties ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
5083 Aluminum Alloy

5083 aluminum alloy was investigated with respect to its uniaxial dynamic compressive properties over a range of strain rates using the split Hopkinson pressure bar (SHPB). The dynamic stress-strain curves of this alloy were obtained for strain rates from 1000 s-1 to 6000 s-1. Effects of strain rate, the samples size and anti-impact capability were analyzed. The experimental results show that under impaction loading, 5083 aluminum alloy has a remarkable strengthening response to strain rate and size; in particular, the responded stress increases with increasing strain rate, which implies that this alloy has high strength and high anti-impact capability.

Strain Rate Effect on Dynamic Compressive Failures in Off-Axis Glass-Epoxy Composites

2000 ◽  
Author(s):  
Jialin Tsai ◽  
C. T. Sun
Keyword(s):  
Shear Modulus ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Rate Dependent ◽  
Bifurcation Buckling ◽  
Split Hopkinson ◽  
Pressure Bar

Abstract Dynamic compressive strength of off-axis S2/8552 glass-epoxy composite in the form of fiber microbuckling was studied. Based on the bifurcation buckling analysis, the microbuckling stress is approximately equal to the composite tangent shear modulus. Using a viscoplastic constitutive model to describe the composite tangent shear modulus, microbuckling stresses at various strain rates were predicted. Small angle off-axis composite specimens were tested to failure at various strain rates. For strain rates below 1/sec, the compression tests were conducted on an MTS machine, while higher strain rate tests were carried out using a Split Hopkinson Pressure Bar (SHPB). Fiber microbuckling was found to be the dominant failure mode for 5°, 10° and 15° specimens within the range of tested strain rates. Comparison of model prediction with experimental data shows that the rate-dependent microbuckling model can be used for predicting compressive strengths at strain rates up to 1100/s.

High-Strain-Rate Failure of a Porous Heterogeneous Composite: Balsa Wood

2001 ◽  
Author(s):  
M. Vural ◽  
G. Ravichandran
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Balsa Wood ◽  
Split Hopkinson ◽  
Pressure Bar

Abstract The compression behavior of a naturally occurring porous and heterogeneous biocomposite, balsa wood, along the grain direction is investigated at strain rates 10−3 to 104 s−1. Specimens with different densities, ranging from 55 to 380 kg/m3, were loaded by a modified Kolsky (split Hopkinson) pressure bar apparatus at varying high strain rates and by a screw-driven testing machine at quasi-static strain rates. The mechanical response of balsa wood is documented and the variation of compressive strength, crushing stress and densification strain as a function of density and strain rate is presented. Results show that characteristics of mechanical response for balsa wood are significantly affected by the strain rate and density.

Effect of Thermobaric Explosive on Strain Rate

2014 ◽  
Vol 1081 ◽  
pp. 348-352
Author(s):  
Ning Ning Zhao ◽  
Bo Liang Wang ◽  
Xi Li
Keyword(s):  
Strain Rate ◽  
Functional Relationship ◽  
Split Hopkinson Pressure Bar ◽  
Stress And Strain ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Testing Technology ◽  
Strain Testing ◽  
Split Hopkinson ◽  
Pressure Bar

In order to analyze the effect of RDX-based thermobaric explosive on strain rate, the stress-strain curves with different strain rates were measured by using the Split Hopkinson Pressure Bar (SHPB) and resistive strain testing technology. The different strain rates were obtained by changing the length to diameter ratio (L/D=0.46~0.92) and speed of the bullet (10~18m/s). The results showed that it is obvious to change the strain rate by the change of the L/D and speed of the bullet with different functional relationship; RDX-based thermobaric explosives have the evident strain rate: failure stress and strain are increased with the increase of strain rate.

Dynamic Behaviors of near β-Type Ti-5Al-5Mo-5V-3Cr Titanium Alloys under High Strain Rate

2015 ◽  
Vol 816 ◽  
pp. 795-803
Author(s):  
Yan Ling Wang ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Rui Liu
Keyword(s):  
Strain Rate ◽  
Titanium Alloys ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Failure Behavior ◽  
Hopkinson Pressure Bar ◽  
Fracture Failure ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Dynamic Loading Conditions

The mechanical properties and fracture failure behavior of the near β-type Ti-5Al-5Mo-5V-3Cr-X (X = 1Fe or 1Zr) titanium alloys were studied by Split Hopkinson Pressure Bar (SHPB) experiment under the dynamic loading conditions at a strain rate of 1.5 × 103 s-1–5.0 × 103 s-1. Results showed that the SHPB specimen fractured in the direction of maximum shearing stress at an angle of 45° with the compression axis. The fracture surface revealed the shear and tension zones with cleavage steps and parabolic dimples. Severe early unloading was observed on the Ti-5553 alloy under a strain rate of 4,900 s-1 loading condition, and the dynamic property of the Ti-55531Zr alloy was proved to be the optimal.

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