共查询到10条相似文献，搜索用时 156 毫秒
1.
GUO Xing-ming Shaghi Instihae of Applied Mathematics Mechanics Shanghai University Shanghai China 《上海大学学报(英文版)》2000,(Z1)
1 IntroductionClassical thermodynamics with the Parabolic-typeFourier heat conduction equation predictS that if amaterial conducting heat is subjected tO a thermaldissonance, the effectS of distalance will be feltinstancously at distances infndtely far from its source. Inother words, thermal signals Propagate at infinite speed.This Prediction is ~listic born a physical point ofview (see Ref.[l]). TO overcome such ~asonablenessand avoid the above situations, The new theory is setusually in … 相似文献
2.
振动剪切作用下LDPE和HDPE熔体的非仿射网络结构模型 总被引：1，自引：0，他引：1
We propose molten polymer‘s entanglement network deformation to be nonaffine and use transient network structural theory with the revised Liu‘s kinetics rate equation and the revised upper convected Maxwell constitutive equation to establish a nonaffine network Structural constitutive model for studying the rheological behavior of molten Low-Density Polyethylene(LDPE)and High Density Polyethylene(HDPE)in oscillatory shear.As a result,when the strain amplitude or frequency increases,the shear stress amplitude increases.At the same time,the accuracy of the nonaffine network model is higher than that of affine network model.It is clear that there is a small amount of nonaffine network deformation for LDPE melts which have long-chain branches,and there is a larger amount of nonaffine network deformation in oscillatory shear for HDPE melts which has no long-chain branches.So we had better consider the network deformation nonaffine when we establish the constitutive equations of polymer melts in oscillatory shear. 相似文献
3.
JIANG Wugui FU Mingfu CHEN Liangsen GENG Shiqi Department of Materials Science Engineering Nanchang Institute of Aeronautical Technology Nanchang Jiangxi P.R. China Institute of Engineering Mechanics Nanchang University Nanchang Jiang 《重庆大学学报(英文版)》2004,3(1):78-81
~~6.ConclusionsJaumannsrate,FusrateandWusratewereincorporatedintotheendochronicequationstoanalyzesimpleshearfinitedeformation.Incrementalequationsandnumericalsolutionsarepresentedforthreeendo-chronicobjectivemodels.TheresultsshowthatanoscillatoryshearstressresponsetoamonotonicallyincreasingshearstrainoccurswhentheJaumannsrateobjectivemodelisemployedforendochronicmaterials.Theoscillatoryresponseisdependentontheadoptedobjectiverate.ComparedwiththeJaumannsrate,theFusrateandtheWusratesatisfythe… 相似文献
4.
The endochronic equations proposed by Valanis (1980) were extended to a finite deformation range. Jaumann's rate,Fu's rate and Wu's rate were incorporated into the endochronic equations to analyze simple shear finite deformation. Incremental equations and numerical solutions are deduced for three endochronic objective models. The results show that an oscillatory shear stress response to a monotonically increasing shear strain occurs when the Jaumann's rate objective model is employed for endochronic materials. The oscillatory response is dependent on the adopted objective rate. Compared with the Jaumann's rate, the Fu's rate and the Wu's rate satisfy the restrictions to elastic-plastic constitutive relations and are in agreement with the experimental results. 相似文献
5.
以2A11铝合金材料为例，采用美国MTS公司生产的MTS810 Material Test system对棒材试样作简单拉伸试验。运用Matlab的多项式运算函数对拉伸试验真应力．自然应变曲线非线性均匀变形阶段进行拟舍，建立了真应力一自然应变本构方程；误差分析表明，精度较高。研究结果为铝舍金材料真应力一自然应变本构方程的建立提供了新的方法，对工程实际应用具有很好的指导意义和参考价值。 相似文献
6.
陈耀庚 《咸阳师范学院学报》2011,26(6)
从功能梯度材料的弹性理论出发,首先推导出梯度材料在不同边界条件下的状态方程,进而使用Fourier变换技术将含裂纹弹性材料与梯度材料粘接的接触问题转化为边值问题,建立起该数学模型。构造带技巧性的积分变换方法将混合边值问题化为奇异积分方程,并利用Gauss—Chebyshev积分公式将奇异积分方程离散为计算机可实现的代数方程组,编制计算机程序并上机调试,得出数值模拟结果。 相似文献
7.
We proposed a bilinearity constitutive curve model of fiber reinforced polymer （FRP） confined concrete which includes a parabola in the first stage and a straight line in the second stage. The FRP-confined concrete has powerful confinement status and weak confinement status leading to different equations of parabola. We analyzed the impacts of factors such as confinement ratio and restrain stiffness on confined concrete compressive strength, ultimate strain and other control parameters through finite element analysis. The results show that the confinement ratio determines the confinement status, and the increase of the confinement ratio has a limited capacity to increase the compressive strength, The deformation of confined concrete is influenced by restrain stiffness. The stronger the restrain stiffness is, the less the lateral deformation is and the greater ultimate axial strain will be. The consideration of equivalent section coefficient kse is needed in the non-circular section confined concrete. We analyzed the results and proposed boundary values of strong and weak confinement styles, a peak/inflection point stress and strain model, and a compressive strength and ultimate strain model. 相似文献
8.
陈玉香 《昆明师范高等专科学校学报》2010,32(3):100-103
从热传导的基本方程出发,介绍结构瞬态温度场和应力场有限元一般格式.编制东京新丰州变电所围护结构二维温度场有限元分析程序,采用ANSYS工程分析软件,计算该围护结构在环境温度变化过程中引起的温度场、温度应力及温度变形,同时计算了在开挖土压力作用下该围护结构的内力与变形,将两种变形与实测变形值进行比较.结果显示,环境温度变化对类似工程围护结构的内力与变形有不可忽视的影响,必须加以计算. 相似文献
9.
丁红珍 《顺德职业技术学院学报》2007,5(2):23-26
研究了Alsi/al梯度铝合金压制板材在热轧大塑性变形后的组织、成分和性能变化,特别是梯度过渡区的塑性变形特征。结果说明:在变形温度为757K下,压制态合金板材经过热轧的大塑性变形后仍然保持着良好的梯度分布特征。随着变形量的增加,热轧板材梯度过渡层的非均匀性有所减少,芯部显微硬度值有所增加。 相似文献
10.
郭大鹏 《湖南科技学院学报》2005,26(11):11-12
二阶非线性椭圆型边值问题因其广泛的实际背景颇受关注,张志军对其在R^N中的有界光滑区域时讨论了解的存在性,并给出了解的最小爆炸速度.现进一步讨论二阶拟线性椭圆型方程在含梯度项情况下爆炸解的存在性. 相似文献