Mechanical Properties of Kevlar® KM2 Single Fiber

2005 ◽  
Vol 127 (2) ◽  
pp. 197-203 ◽  
Author(s):  
Ming Cheng ◽  
Weinong Chen ◽  
Tusit Weerasooriya
Keyword(s):  
Isotropic Material ◽  
Axial Stress ◽  
Axial Loading ◽  
Strain Range ◽  
Transversely Isotropic ◽  
Axial Direction ◽  
Strain Response ◽  
Transversely Isotropic Material ◽  
Stress Strain ◽  
Strain Behavior

Kevlar® KM2 fiber is a transversely isotropic material. Its tensile stress-strain response in the axial direction is linear and elastic until failure. However, the overall deformation in the transverse directions is nonlinear and nonelastic, although it can be treated linearly and elastically in infinitesimal strain range. For a linear, elastic, and transversely isotropic material, five material constants are needed to describe its stress-strain response. In this paper, stress-strain behavior obtained from experiments on a single Kevlar KM2 fiber are presented and discussed. The effects of loading rate and the influence of axial loading on transverse and transverse loading on axial stress-strain responses are also discussed.

THE ANALYSIS OF DYNAMICAL RESPONSE OF TRANSVERSELY ISOTROPIC MATERIAL UNDER BLASTING LOAD

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1443-1448
Author(s):  
YUE-XIU WU ◽  
QUAN-SHENG LIU
Keyword(s):  
Isotropic Material ◽  
Peak Velocity ◽  
Transversely Isotropic ◽  
Normal Direction ◽  
Dynamical Response ◽  
Transversely Isotropic Material ◽  
Peak Acceleration ◽  
Loading Direction ◽  
Blasting Load ◽  
Explosion Load

To understand the dynamic response of transversely isotropic material under explosion load, the analysis is done with the help of ABAQUS software and the constitutive equations of transversely isotropic material with different angle of isotropic section. The result is given: when the angle of isotropic section is settled, the velocity and acceleration of measure points decrease with the increasing distance from the explosion borehole. The velocity and acceleration in the loading direction are larger than those in the normal direction of the loading direction and their attenuation are much faster. When the angle of isotropic section is variable, the evolution curves of peak velocity and peak acceleration in the loading direction with the increasing angles are notching parabolic curves. They get their minimum values when the angle is equal to 45 degree. But the evolution curves of peak velocity and peak acceleration in the normal direction of the loading direction with the increasing angles are overhead parabolic curves. They get their maximum values when the angle is equal to 45 degree.

scholarly journals Elastic-plastic transition stresses in a transversely isotropic thick-walled cylinder subjected to internal pressure and steady-state temperature

2009 ◽  
Vol 13 (4) ◽  
pp. 107-118 ◽  
Author(s):  
Thakur Pankaj
Keyword(s):  
Steady State ◽  
Internal Pressure ◽  
Isotropic Material ◽  
Internal Surface ◽  
Transversely Isotropic ◽  
Percentage Increase ◽  
Transversely Isotropic Material ◽  
Elastic Plastic ◽  
Steady State Temperature ◽  
Walled Cylinder

Elastic-plastic transitional stresses in a transversely isotropic thick-walled cylinder subjected to internal pressure and steady-state temperature have been derived by using Seth's transition theory. The combined effects of pressure and temperature has been presented graphically and discussed. It has been observed that at room temperature, thick-walled cylinder made of isotropic material yields at a high pressure at the internal surface as compared to cylinder made of transversely isotropic material. With the introduction of thermal effects isotropic/transversely isotropic cylinder yields at a lower pressure whereas cylinder made of isotropic material requires less percentage increase in pressure to become fully-plastic from its initial yielding as compared to cylinder made of transversely isotropic material.

Design of a Micro Tensile Testing Structure to Restrain Non-Axial Alignment Errors

2007 ◽  
Author(s):  
Duanqin Zhang ◽  
Jinkui Chu ◽  
Hongyuan Shen
Keyword(s):  
Tensile Test ◽  
Tensile Testing ◽  
Axial Stress ◽  
Vertical Direction ◽  
Axial Loading ◽  
Axial Direction ◽  
Tensile Specimen ◽  
Spring Constant ◽  
Uniaxial Tensile ◽  
Axial Alignment

Accurate mechanical properties measurements in the micro scale are very important for the design and the fail-safe analysis of MEMS. And the tensile test, as one of the micromechanical experimental techniques, has the advantage of uniform stress and strain fields. In this paper, a new tensile testing structure is presented to solve the non-axial alignment problem in microscale tensile test. The testing structure integrates the specimen and the suspended spring beams on a chip. The function of the additional spring beams is to balance the non-axial loading component and so the specimen is uniaxial tensile. As the spring constant of the tensile specimen in the axial direction is much smaller than the spring constant of the testing structure in the vertical direction, the spring beams could specimen caused by non-axial force. Meanwhile, the spring constant of the specimen in axial direction is much larger than that of the spring beams in the same direction so that the loading shared in the spring beams can be ignored. The performance of the tensile testing structure is confirmed by FE simulations. When the loading force has 2° angle with the axial direction, the stress distribution of the specimen is almost identical with that of under axial loading. The axial stress of the specimen is considerably uniform. That is to say the specimen is uniaxially tensile, although the loading direction is offset the axial. And the force shared in the suspended spring beams is below 3.2% of the loading force. The tensile testing structure could greatly weaken the errors caused by disalignment, and would have big potential to be used in the microscale tensile test.

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