拉伸应变

The experimental results are analyzed using the virtual linear viscous theory and the constitutive equation is established for the fibrocartilage.

通过对新鲜腕关节软骨板共计60个试件进行不同应变水平下的"应力松弛试验"和等应变速度下的"拉伸试验"，了解腕关节软骨板在承受一维拉伸破坏试验时的力学性质，并用拟线性粘弹性理论对试验结果进行分析，建立了腕关节软骨板的本构方程。

The value of strain-hardening coefficient can be determined from the slope of logσ-logε curve, which is numerically equal to the maximum uniform true strain. So the strain-hardening coefficient can be used to evaluate the extend of uniform plastic deformation.

由拉伸实验得到的logσ-logε曲线的斜率即为应变硬化指数，其数值与材料拉伸变形时的最大均匀应变相等，是衡量材料塑性均匀变形能力的力学指标。

The dynamic tensile test was carried out on five TWIP steels with strain rates in the range of 102 ~103S-1 by employing a pneumatic indirect bar-bar tensile impact tester, and the results was compared to the static tensile behavior.

采用气动式间接杆杆型冲击拉伸试验装置对5种不同成分的TWIP钢在102~103S-1应变速率范围内的动态拉伸变形行为进行了研究，并和静态拉伸性能作了比较。

The experimental results show that 0.2%yield she ar stress, ultimate shear stress and 0.2%yield tensile stress, ultimate tensile stress under torsion-tension combined high strain-rate decrease with increasi ng temperature.

试验结果表明：该材料在高应变率扭-拉复合加载下的名义剪切屈服强度、剪切强度极限和名义拉伸屈服极限、拉伸强度极限均随温度的升高而降低。

The result of SSRT showed that the tensile strength in fusion zone of LBW weldment is higher than base metal, and the IGC in weld decay zone did not crack because of the stretch;IGC in fusion zone of GTAW weldment leads to early fracture, and the IGC in weld decay zone clearly stretched and cause the material to crack. Intergranular stress corrosion cracking in this section is still possible.

慢应变速率拉伸试验结果，LBW焊件之焊道强度高於母材，且於焊接衰化区所造成之沿晶腐蚀并未因拉伸造成开裂；GTAW焊件的焊道沿晶腐蚀导致断裂提早发生，且在焊接衰化区的沿晶腐蚀明显拉伸造成开裂情形，仍有在此区域发生沿晶应力腐蚀破坏的可能。

When NiTi alloy was tensiled at 600 ℃ and at a lower strain rate, the dynamic recrystallization occurred. Without electric field the stress-strain curves were characterized by periodical undee graph, while under the electric field they presented steady state. When deformation under the electric field, both strain hardening and recrystallization take place simultaneously, thus the flow stress curves exhibits steady state.

NiTi合金高温拉伸变形过程中会发生动态再结晶，在应变速率较低时其应力-应变曲线呈周期性波浪形，在应变速率较高时其应力-应变曲线则呈现较平滑稳定的态势；施加电场作用时抑制了这种周期波浪形变化，使应力-应变曲线呈平滑稳态变化。

The main research tasks and results are as follows:(1) Through comparing the stress intensity factor of compact tension specimen calculated by finite element software with the theoretical value, the feasibility of calculating fracture parameters of crack tip in ABAQUS software was verified.(2) The relationship between the elastic modulus of the material and research scale was studied based on deriving the cohesive stress theory and other relevant theories. And the elastic modulus of the material on meso-scale was determined.(3) Global model and sub-model of the finite element were built in th...e macro-scale, and stress-strain field nearby the crack tip was analyzed, and the results show that the detailed stress-strain in the crack tip could be obtained by using the sub-model technique.(4) In meso-scale, the crack growth model was also established by assuming the crack propagating along the grain boundary, and the detailed stress-strain field in the crack tip was obtained.(5) The effect of crack length on Von Mises stress, and maximum principal stress and strain was analyzed in meso-scale when equivalent KI equals 30MPa.m1/2. And the results show that except for crack tip area, the stress-strain distribution in whole specimen is not affected.

主要完成研究内容和取得成果如下：(1)利用有限元软件计算出紧凑拉伸试样的裂纹尖端应力强度因子KI值，其结果与理论值一致，从而验证了利用ABAQUS计算裂纹尖端相关断裂参量的可行性；(2)在研究内聚应力等相关理论的基础上，推导出了研究尺度与材料弹性模量的近似关系，并确定了介观尺度上的弹性模量；(3)在宏观尺度上建立了全局有限元计算模型和子模型，得到了裂纹尖端应力应变场分布，结果表明利用子模型技术获得比较准确的裂纹尖端应力应变场分布是可行的；(4)在介观尺度上利用平均晶粒尺度的方式建立了裂纹沿晶扩展模型，得到了裂纹尖端断裂过程区的微观应力应变场；(5)当应力强度因子为30MPa.m1/2时，分析了介观尺度上在裂纹沿晶扩展过程中裂纹长度对Mises应力、最大主应力和应变的影响，结果表明，裂纹扩展长度对试样整体应力应变分布影响不大，而对裂纹尖端区域有较大影响；(6)介。。。

The results indicate that the tensile flow stress of the composite sheet decreases with increasing deformation temperature and decreasing strain rate,while the maximum elongation to failure increases from 5.03% to 71.07%.

摘 要：当温度为300~450 ℃，应变速率为0.001~0.1 s1时，在WDW-E200拉伸机上采用单向拉伸实验研究喷射沉积7075Al/SiCp复合材料板材的高温变形行为；分析板材的变形激活能以及流变应力、变形温度和应变速率之间的关系。

The flow behavior of 5182 aluminum alloy for automotive body sheet at the strain rate ranging from 0.001 to 0.1 /s and temperature ranging from 323 to 573 K was studied on Instron8032 tensile tester. A constitutive equation using up-dated Fields-Backofen equation was established to describe the flow behavior of 5182 aluminum alloy during warm tensile.

摘 要：在变形温度为323~573 K、应变速率为0.001~ 0.1 /s条件下，采用Instron8032电子拉伸实验机对汽车用5182铝合金板的流变行为进行研究，采用修正后的Fields- Backofen方程描述5182铝合金温拉伸时的流变行为，建立5182铝合金在温拉伸时的应力－应变本构模型。

The corresponding relations between the strain of the static state and dynamic cycle load and the volume resistance of the short chopped carbon fibers, short chopped carbon mat, unidirectional carbon fibers reinforced vinyl resin composites is existed. The physical modes of these kinds of composites are also designed based on the experiment data. The resistance and strain of the short chopped fibers reinforced vinyl composites satisfy the equation of y =A + Bx + Cx~2 in the static strain test method and the short chopped mat reinforced vinyl composites is y = A + Bx.

短切碳纤维、短切碳纤维毡、单向碳纤维增强乙烯基酯树脂复合材料在静态和动态循环载荷下，应变与电阻之间有较好的对应性，同时根据实验数据，建立了不同条件下该复合材料应变和电阻变化规律的物理模型，短切碳纤维增强乙烯基酯树脂复合材料在静态拉伸时电阻与应变之间满足：y=A+Bχ+Cχ~2；碳纤维毡增强乙烯基酯树脂复合材料在静态拉伸破坏时电阻与应变之间满足：y=A+Bχ。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。