Quasi-Static Tensile Properties and Damage Mechanism of Three-Dimensional Angle-Interlock Woven Composites

2012 ◽  
Vol 182-183 ◽  
pp. 148-152
Author(s):  
Kun Luan ◽  
Fa Zhang ◽  
Li Wei Wu

The uniaxial tensile properties of three-dimensional angle-interlock woven composites (3DAWCs) under quasi-static loading were investigated in this paper. The samples were manufactured into dog-bone shape and tested on Material Test System 810.23. The strain-stress curves in warp direction indicating the Young’s moduli, maximum stress and maximum strain are achieved from the uniaxial tensile test. The effects of microstructure and damage morphology of 3DAWC under quasi-static tension are discussed. Furthermore, we will focus on the energy absorption mechanism from the view of tensile failure mode. The material parameters of 3DAWC in warp direction can be evaluated for developing quantitative approach to design polymer matrix composite structures.

2011 ◽  
Vol 82 (3) ◽  
pp. 280-287 ◽  
Author(s):  
Xuehui Gan ◽  
Jianhua Yan ◽  
Bohong Gu ◽  
Baozhong Sun

The uniaxial tensile properties of 4-step 3D braided E-glass/epoxy composites under quasi-static and high-strain rate loadings have been investigated to evaluate the tensile failure mode at different strain rates. The uniaxial tensile properties at high strain rates from 800/s to 2100/s were tested using the split Hopkinson tension bar (SHTB) technique. The tensile properties at quasi-static strain rate were also tested and compared with those in high strain rates. Z-transform theory is applied to 3D braided composites to characterize the system dynamic behaviors in frequency domain. The frequency responses and the stability of 3D braided composites under quasi-static and high-strain rate compression have been analyzed and discussed in the Z-transform domain. The results indicate that the stress-strain curves are rate sensitive, and tensile modulus, maximum tensile stress and corresponding tensile strain are also sensitive to the strain rate. The tensile modulus, maximum tensile stress of the 3D braided composites are linearly increased with the strain rate. With increasing of the strain rate (from 0.001/s to 2100/s), the tensile failure of the 3D braided composite specimens has a tendency of transition from ductile failure to brittle failure. The magnitude response and phase response is very different in quasi-static loading with that in high-strain rate loading. The 3D braided composite system is more stable at high strain rate than quasi-static loading.


Author(s):  
Stijn Hertelé ◽  
Timothy Galle ◽  
Koen Van Minnebruggen ◽  
Wim De Waele ◽  
Otto Jan Huising

Standard pipe corrosion assessments are based on simplifying assumptions with respect to corrosion geometry and focus on pressure based loading. Moreover, when corrosion patches traverse girth welds, validity criteria to their assessment become impractically vague. The integrity of girth welds is additionally influenced by axial stresses, which may act in combination with hoop stress resulting from pressure. In an attempt to address these issues, the authors conducted a detailed assessment on a significant, highly irregular corrosion patch traversing a 12″ natural gas pipeline girth weld. The investigation comprises a full scale uniaxial tensile test and supporting detailed finite element (FE) analyses. Hereby, the model mesh adopts detailed geometrical characteristics resulting from a surface profile scan obtained from stereoscopic digital image correlation. The numerical model is validated based on the uniaxial tensile test, in the sense that plastic collapse and highly complex strain distributions are successfully reproduced. Finally, the FE model is used to explore axial tensile failure in presence of internal pressure.


Author(s):  
Eun-chae Jeon ◽  
Joo-Seung Park ◽  
Doo-Sun Choi ◽  
Kug-Hwan Kim ◽  
Dongil Kwon

The instrumented indentation test, which measures indentation tensile properties, has attracted interest recently because this test can replace uniaxial tensile test. An international standard for instrumented indentation test has been recently legislated. However, the uncertainty of the indentation tensile properties has never been estimated. The indentation tensile properties cannot be obtained directly from experimental raw data as can the Brinell hardness, which makes estimation of the uncertainty difficult. The simplifying uncertainty estimation model for the indentation tensile properties proposed here overcomes this problem. Though the influence quantities are generally defined by experimental variances when estimating uncertainty, here they are obtained by calculation from indentation load-depth curves. This model was verified by round-robin test with several institutions. The average uncertainties were estimated as 18.9% and 9.8% for the indentation yield strength and indentation tensile strength, respectively. The values were independent of the materials’ mechanical properties but varied with environmental conditions such as experimental instruments and operators. The uncertainties for the indentation yield and tensile strengths were greater than those for the uniaxial tensile test. These larger uncertainties were caused by measuring local properties in the instrumented indentation test. The two tests had the same tendency to have smaller uncertainties for tensile strength than yield strength. These results suggest that the simplified model can be used to estimate the uncertainty in indentation tensile properties.


2019 ◽  
Vol 224 ◽  
pp. 111025 ◽  
Author(s):  
Gautam Prabhu ◽  
Vivek Katakam ◽  
Vijay Shankar Sridharan ◽  
Sridhar Idapalapati

2021 ◽  
Vol 1035 ◽  
pp. 25-31
Author(s):  
Hai Feng Wan ◽  
Ai Jun Xu ◽  
Yun Long Huang ◽  
Ze Jun Tang

The effects of pulse current on the tensile properties of high temperature titanium alloy Ti55 were investigated by pulse current assisted uniaxial tensile test under different electrical parameters. It was found that with the increase of peak current and pulse width, the tensile properties of Ti55 are significantly improved. At the same time, the pulsation effect of current on the mechanical properties of Ti55 was investigated. The results show that the tensile displacement of low pulsation group was higher, while the elongation of high pulsation group was higher. In order to explore the mechanism of pulsation effect of current, EBSD was adopted. The results indicated that high pulse current can significantly promote the dislocation movement and recrystallization. In addition, some macrozones was found in low pulsation group, which indicated that high pulsation current was more suitable for material forming than low pulsation current.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Addis Kidane

An experimental study is performed to investigate the tensile failure and fracture behavior of polymer foam containing discontinuities. PVC corecell foam, series A800 and A1200 is used for the investigation. Unnotched dog-bone specimen and specimens with center hole and edge cracks are tested under uniaxial tensile loading. Series of experiments are conducted at different defect size to width ratios, and the effect of the defect size on the net-section tensile strength of the foam is investigated. A fracture study is also conducted, and the effect of density and loading rate on the fracture behavior of foam is investigated. A minimal notch-strengthening effect is observed in specimens with center hole, and a notch-weakening effect is observed in specimen with edge notches. Furthermore, the fracture toughness increases with the increase in the foam density and decreases with the increase in loading rate.


Author(s):  
Kug-Hwan Kim ◽  
Kyung-Woo Lee ◽  
Ju-Young Kim ◽  
Dongil Kwon ◽  
Kwang-Ho Kim

Instrumented indentation technique (IIT) is a novel tool to estimate mechanical properties such as tensile properties, residual stress and fracture toughness by analyzing indentation load-depth curve measured during loading-unloading of indentation. It can be applied directly in small-scale and localized sections of pressure vessel and pipeline since the preparation of specimen is very easy and the experimental procedure is feasible and nondestructive. We present the principles developed for measuring mechanical properties using IIT; the tensile properties by defining the representative stress and strain underneath a spherical indenter, the residual stress near the weldments using the stress-insensitive contact hardness model, and the fracture toughness of ductile metal based on critical indentation energy model. The experimental results from IIT were verified by comparing the results from the conventional methods such as uniaxial tensile test for tensile properties, mechanical saw-cutting and hole-drilling methods for residual stress, and CTOD test for fracture toughness. In particular, the applications of IIT in small scale materials and localized sections of the pressure vessel and pipeline in-use and in-fields are presented.


Author(s):  
M. D. Mathew ◽  
J. Ganesh Kumar ◽  
V. Ganesan ◽  
K. Laha

AbstractType 316L(N) stainless steel (SS) containing 0.02–0.03 wt% carbon and 0.06–0.08 wt% nitrogen is used as the major structural material for the components of fast reactors. Research is underway to improve the high-temperature mechanical properties of 316LN SS by increasing the nitrogen content in the steel above the level of 0.08 wt%. In this investigation, ball indentation (BI) technique was used to evaluate the effect of nitrogen content on the tensile properties of 316LN SS. BI tests were conducted on four different heats of 316LN SS containing 0.07, 0.11, 0.14 and 0.22 wt% nitrogen in the temperature range 300–923 K. The tensile properties such as yield strength and ultimate tensile strength increased with increase in nitrogen content at all the investigated temperatures. These results were consistent with the corresponding uniaxial tensile test results. These studies showed that BI technique can be used to optimize the chemical composition during alloy development by evaluating tensile properties with minimum volume of material.


2017 ◽  
Vol 36 (10) ◽  
pp. 725-738 ◽  
Author(s):  
Xiao-Kang Li ◽  
Zhen-Guo Liu ◽  
YuChen Wei ◽  
Xiang Huang ◽  
Bing Lei

Adhesive bonding is usually used to fabricate composite structures that are hard to manufacture in one piece, however, their lightweight advantage is usually impaired by low failure strength. For high performance composite structures, bonding properties of joints dominate the failure performance and commonly are the primary target of structural optimization. Both experimental and numerical studies of failure behavior of single-lap joints with three-dimensional braided composite laminate adherends are presented in this paper. First, tensile failure tests were performed on braid-laminates single-lap joints bonded with epoxy resin. Compared with the laminates–laminates single-lap joints, the failure load of the braid–laminates single-lap joints increased by 18.4%. Then, the Finite Element Method (FEM) coupled with cohesive zone models (CZM), considering different value of overlap length (L), was used to perform the detail stress distribution of the overlap sections of SLJs. Further, damage initialization and crack growth of single-lap joints are analyzed in detail to fully characterize the failure process, and both experimental and numerical results lead to the same conclusion. Lastly, the effect of three-dimensional braided adherends’ braiding angle on braid-laminates single-lap joints’ performance was investigated, which provides suggestions for the design and optimization for adhesive bonded composite structures.


2016 ◽  
Vol 853 ◽  
pp. 46-50 ◽  
Author(s):  
Xiang Qing Li ◽  
Chuan Xiao Wu ◽  
Jian Feng Mao ◽  
Shi Yi Bao ◽  
Zeng Liang Gao

Three-dimensional (3D) elastic-plastic finite element model (FEM) is adopted to research the effect of side groove on the crack-front J-integral for different size of Compact Tension (CT) specimens. Although the side-grooved CT specimen is widely used in the existing test method, such as ASTM E1820-13, the test data of fracture toughness is varying with the various geometric parameters. Before FE calculation, the material properties of Q345 steel were obtained by uniaxial tensile test, especially for the true stress-strain relationship. In this paper, it focuses on the numerical study of geometric parameter effects on the fracture toughness. Toward this end, the commercial FE software of ABAQUS is adopted to calculate the J-integral. Since the side groove of CT specimen is so important to make the fracture test success, the various parameters of side groove is intensively analyzed for obtaining the accurate J-integral along the crack front, including the effects of the angle, depth and root radius. In fact, the side groove effect is so significant around the crack front that cannot be ignored in the J-integral calculation. Through rigorous FE investigation, the influence of the side groove on the fracture toughness testing is fully disclosed, and the appropriate side groove configuration is recommended accordingly.


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