GS0327 Viscoelastic Characteristic Evaluation under High Strain Rate by Impact Test

2016 ◽  
Vol 2016.22 (0) ◽  
pp. _GS0327-1_-_GS0327-2_
Author(s):  
Ken TSUCHIHASHI ◽  
Satoru YONEYAMA
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Impact Test ◽  
High Strain ◽  
Viscoelastic Characteristic

Influence of Temperature on Dynamic Behavior of Rubber Materials by Taylor Impact Test

2011 ◽  
Vol 673 ◽  
pp. 83-88 ◽  
Author(s):  
Hyung Seop Shin ◽  
Sung Su Park ◽  
Joon Hong Choi
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Speed ◽  
Impact Test ◽  
High Strain ◽  
High Speed Photography ◽  
Impact Tests ◽  
Taylor Impact ◽  
Taylor Impact Test

The understanding of the deformation behavior of rubber materials under high strain-rate or high loading-rate conditions will be important in their impact applications adopting significant viscoelastic behavior. Taylor impact test has originally used to determine the average dynamic yield strength of metallic materials at high strain rates, but it also can be used to examine the overall deformation behavior of rubbers representing large elastic deformation by using a high-speed photography technique. Taylor impact tests of rubber materials were carried out in the velocity range between 100~250 m/s using a 20 mm air gun. In order to investigate the overall dynamic deformation behavior of rubber projectiles during Taylor impact test, a 8-Ch high-speed photography system which provides a series of images at each elapsed time was incorporated. Three kinds of rubber materials with different Tg (glass transition temperature) were supplied. The bulging behavior of rubber projectile could be evaluated quantitatively by digitizing images taken. Taylor impact tests at various temperature levels were conducted to predict the bulging behavior of rubbers at high strain rate.

Static and Dynamic Properties of AC4C Aluminum Alloy

2008 ◽  
Vol 33-37 ◽  
pp. 579-584
Author(s):  
Jeong Seok Oh ◽  
W.K. Ju ◽  
Yi Qi Wang ◽  
Tae Gyu Kim ◽  
Jung I. Song
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Impact Energy ◽  
Impact Test ◽  
Fracture Strain ◽  
High Strain ◽  
Dynamic Properties ◽  
Edge Region ◽  
Plane Region ◽  
Low Strain Rate

The static and dynamic properties on the hoist hook of a vessel are necessary since they are affected by the damages of a static and dynamic load. Al-Si-Mg casting alloy (AC4C-T6) is widely used due to its good mechanical properties as well as the light weight and good casting with complex geometries. This study accomplished a static tension test and an impact test. Based on the test results and fracture surface analysis, we found that there are great differences between the fracture strain and yield stress in the different extracted regions of specimen. In tensile test, yield stress were 205 MPa at a low strain rate of 5 mm/min and 220 MPa at a high strain rate of 25mm/min. In Charpy impact test, impact properties of AC4C aluminum alloy were analyzed by impacting loading versus displacement and impacting energy versus displacement. Compared the fracture strains in different strain rates, maximum fracture strain of low strain rate was mainly 10 % higher than that of high strain rate. There were more than 20 % differences in the strain rate. The ductile and brittle behaviors were showed in low strain rate and high strain rate in static tensile test, respectively. The impact energy reached high when they were extracted from a plane region in the mold. But impact energy reached low when they were extracted from a curved and edge region. It is demonstrated that mechanical properties and impact energy of the samples where were extracted from a curved and edge region was lower than that of the samples where were extracted from a plane region.

scholarly journals Combined shear/tension testing of fibre composites at high strain rates using an image-based inertial impact test

2018 ◽  
Vol 183 ◽  
pp. 02041 ◽  
Author(s):  
Lloyd Fletcher ◽  
Jared Van-Blitterswyk ◽  
Fabrice Pierron
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Stress Wave ◽  
Impact Test ◽  
High Strain ◽  
Hopkinson Bar ◽  
Test Method ◽  
Strain Rates ◽  
Fibre Composites ◽  
Split Hopkinson

Testing fibre composites off-axis has been used extensively to explore shear/tension coupling effects. However, off-axis testing at strain rates above 500 s-1 is challenging with a split Hopkinson bar apparatus. This is primarily due to the effects of inertia, which violate the assumption of stress equilibrium necessary to infer stress and strain from point measurements taken on the bars. Therefore, there is a need to develop new high strain rate test methods that do not rely on the assumptions of split Hopkinson bar analysis. Recently, a new image-based inertial impact test has been used to successfully identify the transverse modulus and tensile strength of a unidirectional composite at strain rates on the order of 2000 -1. The image-based inertial impact test method uses a reflected compressive stress wave to generate tensile stress and failure in an impacted specimen. Thus, the purpose of this study is to modify the image-based inertial impact test method to investigate the high strain rate properties of fibre composites using an off-axis configuration. For an off-axis specimen, a combined shear/tension or shear/compression stress state will be obtained. Throughout the propagation of the stress wave, full-field displacement measurements are taken. Strain and acceleration fields are then derived from the displacement fields. The kinematic fields are then processed with the virtual fields method (VFM) to reconstruct stress averages and identify the in-plane stiffness components G12 and E22.

scholarly journals Shear failure of AA2024 and AA7175 under high strain rate loading

2018 ◽  
Vol 188 ◽  
pp. 02005
Author(s):  
Gunasilan Manar ◽  
Patrice Longère
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Shear Failure ◽  
Impact Test ◽  
High Strain ◽  
Failure Mechanisms ◽  
Electron Microscopes ◽  
Strain Rate Loading ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

In the context of the design of aeronautical structures regarding accidental events, we are here investigating and comparing the shear failure of two aluminum alloys, namely AA2024 and AA7175, under high strain rate loading. With this aim in view, two experiments were carried out: (i) high strain rate shear compression of hat shaped structures, and (ii) impact test on the edge of double notched plates. The fractured surfaces of post-mortem specimens were observed using optical and scanning electron microscopes (SEM) in order to identify the failure mechanisms.

Impact Properties of Hot-Worked Gamma Alloys with BCC β-Ti Phase

2004 ◽  
Vol 842 ◽  
Author(s):  
Kentaro Shindo ◽  
Toshimitsu Tetsui ◽  
Toshiro Kobayashi ◽  
Shigeki Morita ◽  
Satoru Kobayashi ◽  
...  
Keyword(s):  
Tensile Test ◽  
High Strain Rate ◽  
Strain Rate ◽  
Tial Alloy ◽  
Impact Test ◽  
High Strain ◽  
Impact Resistance ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Foreign Object

ABSTRACTImpact resistance of a hot-forged TiAl alloy with a composition of Ti-42∼44Al-5∼10M: M=V, Mn(at%), consisting of lamellar, γ and β grain of which the hot-workability was improved by introducing β phase, has been investigated using an instrumented Charpy impact test, tensile test at high strain rate and foreign object attack test. In instrumented Charpy impact test the absorbed energies for crack initiation and propagation were measured, and the effect of microstructure on the absorbed energies has been analyzed, by paying attention to the grain size, interlamellar spacing and lamellar area fraction. In tensile test at high strain rate, the dependence of strain rate of hot-extruded TiAl alloy is obtained and compared with that of Nickel based superalloy, Inconel 713C. In foreign object attack test with taper plate specimen modified turbine blade and brass ball as foreign object, the relation between impact damage and thickness of specimen at attack point is investigated. A limit of impact energy, at which there isn't a crack on buck of attack point, is obtained with each thickness about hot-forged TiAl alloy, Ti-42Al-5Mn. Therefore, the method of improvement of toughness and assessment of impact resistance of TiAl alloy is shown in this study.

Quasi-Static and Dynamic Characterization of Oil-Based Modeling Clay and Numerical Simulation of Drop-Impact Test

2011 ◽  
Author(s):  
C. Hernandez ◽  
A. Maranon ◽  
I. A. Ashcroft ◽  
J. P. Casas-Rodriguez
Keyword(s):  
Numerical Simulation ◽  
High Strain Rate ◽  
Strain Rate ◽  
Impact Test ◽  
High Strain ◽  
Material Model ◽  
Drop Impact ◽  
Material Constants ◽  
Drop Impact Test ◽  
Modeling Clay

Numerical simulations require the determination of material constants associated to a given mathematical material model that accurately represents its mechanical behavior. Furthermore, for dynamic models, the characterization process should be accomplished at high strain rates since the mechanical properties of some materials are influenced by the rate of loading. This pressure-dependant behavior is commonly seen in paste-like materials such as oil-based modeling clay. This material, is widely used as simulating a material for analyzing metal forming processes, in impact applications as soft body impactor, or as backing material in ballistic resistance testing of body armors. There are many techniques used for characterizing these kinds of pastelike materials. Traditional quasi-static tests, such as compression or indentation, are the most commonly used, although, high strain rate techniques, such as the drop-impact test, are also used when dynamic properties are required. This paper presents the mechanical characterization of an oil-based modeling clay by two different techniques: quasi-static and a high strain rate technique. The results of a traditional quasi-static method, using compression tests, are compared with the constants determined by a proposed high strain rate characterization procedure that uses as input a single drop-impact test. Both sets of material constants are implemented in a numerical simulation that uses the power law plasticity material model. Drop impact numerical simulations and their verification against experimental results were performed to compare the accuracy of both sets of material constants and the suitability of the characterization techniques. Results illustrate that the proposed high strain rate characterization technique show advantages in the determination of the materials constants for the numerical simulation of dynamic events.

Sign in / Sign up

Export Citation Format

Share Document