Investigating Strain Rate Effect on Transverse Compressive Strength of Fiber Composites

2006 ◽  
Vol 306-308 ◽  
pp. 733-738 ◽  
Author(s):  
Jia Lin Tsai ◽  
Jui Ching Kuo
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Shear Failure ◽  
Split Hopkinson Pressure Bar ◽  
Rate Sensitivity ◽  
Fiber Composites ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Epoxy Composites ◽  
Hopkinson Pressure Bar

This research aims to investigate strain rate effect on transverse compressive strength of unidirectional fiber composites. Both glass/epoxy and graphite/epoxy composites were taken into account in this study. To demonstrate strain rate effect, composite brick specimens were fabricated and tested to failure in the transverse direction at strain rate ranges from 10-4/s to 500/s. For strain rate less than 1/s, the experiments were conducted by a hydraulic MTS machine. However, the higher strain rate tests were performed using a Split Hopkinson Pressure Bar (SHPB). Experimental observations reveal that the transverse compressive strengths increase corresponding to the increment of the strain rates. A semi-logarithmic function was employed to describe the rate sensitivity of the transverse compressive strength. SEM photographic on the failure surfaces depicts that for glass/epoxy composites, the failure mechanism is mainly due to the matrix shear failure, however, for the graphite/epoxy composites, it becomes the fiber and epoxy interfacial debonding which could dramatically reduce the transverse compressive strengths of the fiber composites.

High Strain Rate Compressive Behaviour of Selective Laser Melted Ti-6Al-4V

2017 ◽  
Vol 890 ◽  
pp. 323-326 ◽  
Author(s):  
Maziar Ramezani ◽  
Emmanuel Flores-Johnson ◽  
Lu Ming Shen ◽  
Thomas Neitzert
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Shear Failure ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Rate Sensitivity ◽  
Melting Process ◽  
Mechanical Tests ◽  
Hopkinson Pressure Bar

Ti-6Al-4V alloy is one of the most important engineering alloys, combining attractive properties with inherent workability. The aim of this study is to investigate the effect of strain rate on the compressive mechanical properties of Ti6Al4V alloy manufactured by a selective laser melting process. The mechanical tests were performed by means of a compression split Hopkinson pressure bar apparatus under high strain rate ranging from 1400 s-1 to 4500 s-1. The true stress-strain curves obtained from static and dynamic compressive tests show strain rate sensitivity from quasi-static (peak strength 1300MPa) to high strain rate (peak 1500 MPa). Within the high strain rate range tested, the strain rate sensitivity is not remarkable. The fractographic analysis shows a relatively smooth and smeared fractured surface along with a dimple like structure. The observation of elongated dimples confirms the operation of a dynamic shear failure mechanism for the additively manufactured Ti-6Al-4V parts.

Multilevel Analysis of Strain Rate Effect on Visco-Damage Evolution in Short Random Fiber Reinforced Polymer Composites

2021 ◽  
Vol 36 (2) ◽  
pp. 213-218
Author(s):  
M. D. D. Boudiaf ◽  
L. Hemmouche ◽  
M. A. Louar ◽  
A. May ◽  
N. Mesrati
Keyword(s):  
Strain Rate ◽  
Damage Evolution ◽  
Glass Fibers ◽  
Rate Sensitivity ◽  
Polymeric Composite ◽  
Tensile Tests ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Fiber Reinforced ◽  
Stress Levels

Abstract In this study, the strain rate sensitivity of a discontinuous short fiber reinforced composite and the strain rate effect on the damage evolution are investigated. The studied material is a polymeric composite with a polyamide 6.6 matrix reinforced with oriented randomly short glass fibers at a 50% weigh ratio (PA6.6GF50). Tensile tests at low and high strain rate are conducted. In addition, interrupted tensile tests are carried out to quantify the damage at specific stress levels and strain rates. To perform the interrupted tensile tests, an intermediate fixture is realized via double notched mechanical fuses with different widths designed to break at suitable stress levels. The damage is estimated by the fraction of debonded fibers and matrix fractures. Based on the experimental observations, it is concluded that the ultimate stress and strain, and the damage threshold are mainly governed by the strain rate. Furthermore, it is established that the considered composite has a non-linear dynamic behavior with a viscous damage nature.

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.

Effects of Temperature and Strain-Rate on the Compressive Strength of Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 2619-2624
Author(s):  
Chuan Xiong Liu ◽  
Yu Long Li
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Peak Strain ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Compressive Strength Of Concrete ◽  
Pressure Bar ◽  
Increasing Temperature ◽  
Compressive Tests

Dynamic compressive tests were carried out for concrete specimens after exposure to temperatures 23°C, 400°C, 600°C and 800°C by using Split Hopkinson Pressure Bar(SHPB) apparatus. Cylindrical specimens with 98mm in diameter and 49mm in length were used in tests. The strain rates achieved in tests ranged from 30s-1 to 220s-1. The results showed that the compressive strength increases with increasing strain-rate, but decreases with the increase of temperature. However, the effect of strain-rate on improving the compressive strength of concrete decreases with the increase of temperature. Moreover, the strain-rate has an improvement on the peak strain of concrete, and the accretion rate increases with increasing temperature.

Strain-Rate Relationship of Aluminum Matrix Composites Predicted by Johnson-Cook Model

2011 ◽  
Vol 704-705 ◽  
pp. 935-940
Author(s):  
De Zhi Zhu ◽  
Wei Ping Chen ◽  
Yuan Yuan Li
Keyword(s):  
Strain Rate ◽  
Volume Fraction ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Aluminum Matrix ◽  
Rate Sensitivity ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Hopkinson Pressure Bar ◽  
Cook Model

Strain-rate sensitivities of 55-65vol.% aluminum 2024-T6/TiB2composites and the corresponding aluminum 2024-T6 matrix were investigated using split Hopkinson pressure bar. Results showed that 55-65vol.% aluminum 2024-T6/TiB2composites exhibited significant strain-rate sensitivities, which were three times higher than that of the aluminum 2024-T6 matrix. The strain-rate sensitivity of the aluminum 2024-T6 matrix composites rose obviously with reinforcement content increasing (up to 60%), which agreed with the previous researches. The aluminum 2024-T6/TiB2composites showed hybrid fracture characteristics including particle cracking and aluminum alloy softening under dynamic loading. The flow stresses predicted by Johnson-Cook model increased slowly when the reinforcement volume fraction ranged in 10%-40%. While the reinforcement volume fraction was over 40%, the flow stresses of aluminum matrix composites increased obviously and the strains dropped sharply. Keywords: Composite materials; Dynamic compression; Stress-strain relationship

Effect of Surface Modification on Strain Rate Sensitivity of Polypropylene/Muscovite Layered Silicate Composites

2014 ◽  
Vol 803 ◽  
pp. 343-347
Author(s):  
M.F. Omar ◽  
Nur Suhaili Abd Wahab ◽  
Hazizan Md Akil ◽  
Zainal Arifin Ahmad ◽  
Mohd Fadli Ahmad Rasyid ◽  
...  
Keyword(s):  
Surface Modification ◽  
Ion Exchange ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Split Hopkinson Pressure Bar ◽  
Layered Silicate ◽  
Rate Sensitivity ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

Surface modification is one of the treatment methods that can be implemented to improve the strain rate sensitivity of composite materials. In this study, both untreated and treated polypropylene/muscovite layered silicate composites were tested under static and dynamic loading up to 1100 s-1 using the universal testing machine and the split Hopkinson pressure bar apparatus, respectively. Muscovite particles were treated with lithium nitrate and cetyltrimethylammonium bromide as a surfactant through ion exchange treatment. Results show that the treated polypropylene/muscovite specimens with fine state of dispersion level shows better rate of sensitivity as compared to untreated polypropylene/muscovite specimens under a wide range of strain rate investigated. Apart from that, the rate of sensitivity of both tested polypropylene/muscovite layered silicate composites also show great dependency on the strain rate sensitivity was steadily increased with increasing strain rate. Unfortunately, the thermal activation values show contrary trend. Key words: Ion exchange treatment; Strain rate sensitivity; Muscovite particles; Split Hopkinson pressure bar apparatus; Strain rates

scholarly journals Epoxy-glass Microballoon Syntactic Foams for Blast Mitigating Applications

2018 ◽  
Vol 68 (2) ◽  
pp. 210 ◽  
Author(s):  
A.V. Ullas ◽  
P. K. Sharma ◽  
P. Chandel ◽  
P. Sharma ◽  
D. Kumar ◽  
...  
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Hollow Spheres ◽  
Rate Sensitivity ◽  
Syntactic Foams ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Static Regime ◽  
Pressure Bar ◽  
Blast Loadings

Polymeric syntactic foams refer to a class of cellular material created using preformed hollow spheres bound together with a polymeric matrix. These cellular materials possess exceptional ability to respond against high impact dynamic loads. This paper is an attempt to fabricate polymeric syntactic foams of epoxy containing hollow glass microballoon at varying loading (40 % - 60 %) and explore their potential towards blast mitigation. The tensile, compressive and flexural strength were found to be inversely proportional to the microballoon loading in the quasi-static regime. The strain rate sensitivity of the foams was confirmed by performing high strain rate studies using split hopkinson pressure bar. The flow stress of these foams was found to increase with increasing strain rates. The syntactic foams were subjected to controlled transient blast loadings using a shock tube. The samples remained intact and no strain was observed on the strain gauge, even under a blast load of ~ 90 psi, which clearly highlight their potential as core materials for blast mitigating applications.

Mechanism of the Strain Rate Effect of Metal Foams with Numerical Simulations of 3D Voronoi Foams during the Split Hopkinson Pressure Bar Tests

2015 ◽  
Vol 12 (04) ◽  
pp. 1540010 ◽  
Author(s):  
B. Yang ◽  
Z. J. Liu ◽  
L. Q. Tang ◽  
Z. Y. Jiang ◽  
Y. P. Liu
Keyword(s):  
Strain Rate ◽  
Numerical Simulations ◽  
Strain Rate Sensitivity ◽  
Split Hopkinson Pressure Bar ◽  
Rate Sensitivity ◽  
Metal Foams ◽  
Hopkinson Pressure Bar ◽  
Matrix Metal ◽  
The Matrix ◽  
Pressure Bar

With the demand of lightweight structure, more and more metal foams were employed as impact protection and efficient energy absorption materials in engineering fields. But, results from different impact experiments showed that the strain rate sensitivity of metal foams were different or even controversial. In order to explore the true hiding behind the controversial experimental data about the strain rate sensitivity of metal foams, numerical simulations of split Hopkinson pressure bar (SHPB) tests of the metal foams were carried out by finite element methods. In the analysis, cell structures of metal foams were constructed by means of 3D Voronoi, and the matrix metal was assumed to be no strain rate sensitivity, which helps to learn the strain rate effects quantitatively by the foam structures. Numerical simulations showed that the deformation of the metal foam specimen is not uniform during the SHPB tests along the specimen, and the strain–stress relations of the metal foams at two ends of the specimen are different; there exists strain rate sensitivity of the metal foams even the matrix metal has no strain rate sensitivity, when the strain of the metal foams is defined by the displacement difference between the ends of the specimen; localized deformation of the metal foams and the inertia effect of matrix metal are the two main contributions to the strain rate sensitivity of the metal foams.

Sign in / Sign up

Export Citation Format

Share Document