共查询到20条相似文献,搜索用时 15 毫秒
1.
为了研究复杂应力下多孔SMA的超弹性特性,用一热力学有限元模型对带中心孔宽板在双轴拉应力作用下孔临界区域的应力分布以及相变情况进行了有限元模拟计算.初始时,平板处于奥氏体状态,在载荷作用下,在圆孔边界处首先发生相变,并随着载荷的增加,相变区域逐渐向内部扩展.在计算中,两个加载方向同时加载,并采用了不同的加载比例R.随着加载比例的增大,圆孔周围完全发生马氏体相变的区域逐渐增大,等效应力分布也发生变化.随着2-方向加载水平的增加,1-方向的应力-应变滞后环位置逐渐逐渐降低,马氏体相变临界应力也逐渐减小.同时确立了应力空间(σ11,σ12)上的相变初始面. 相似文献
2.
Materials Science - On the basis of solutions of the plane problems of the elasticity theory for a quasiorthotropic body with curvilinear hole, we propose an analytic-numerical algorithm for the... 相似文献
3.
4.
5.
The load separation concept is employed to determine the mixed mode plastic η
pl
and hCODpl{\eta^{COD}_{pl}} factors for the tension plate with an inclined centre throughthickness crack for power law hardening materials. The separation
parameters S
ij
are calculated from the FE computed load – plastic displacement (or COD) curves for each case. It is shown that the mixed
mode plastic η
pl
factor is a function of both the crack angle orientation θ (or the applied elastic parameter M
e
) and the strain hardening exponent. 相似文献
6.
A three-dimensional buckling delamination problem for a rectangular sandwich plate made from elastic and viscoelastic materials is studied. It is supposed that the plate contains interface embedded rectangular cracks and that the edge-surfaces of these cracks have initial infinitesimal imperfections. The evolution of these initial imperfections with an external bi-axial compressed force (for the case where the materials of the layers of the plate are elastic) or with duration of time (for the case where the materials of the layers of the plate are viscoelastic) is investigated. The corresponding boundary value problem is formulated within the framework of the piecewise homogeneous body model with the use of three-dimensional geometrically nonlinear field equations of the theory of viscoelastic bodies. This problem is solved by employing boundary form perturbation techniques, Laplace transform and FEM. According to the initial imperfection criterion, the values of the critical parameters are determined. Numerical results on the critical force and critical time are presented and discussed. In particular, it is established that the values of the critical forces obtained for the buckling delamination around the rectangular embedded interface cracks are significantly greater than those obtained for the corresponding edge and band cracks. 相似文献
7.
We analyze specific features of the design of equipment used for mechanical testing of sheet structural materials under the conditions of biaxial static, cyclic, or dynamic loading. We propose original solutions of the problems related to the fatigue testing of crosslike specimens performed without using complex hydraulic systems and their dynamic testing carried out by using very simple testing machines for uniaxial tension–compression. 相似文献
8.
Within the framework of the theory of Reissner, we study the problem of bending of an isotropic plate of constant thickness with two identical cracks located on the same line under the assumption that a self-balanced load (bending moments) is applied to the crack lips. By using the methods of the theory of functions of complex variable, we reduce the solution of the problem to a system of singular integral equations and solve this system numerically (by the method of mechanical quadratures). We also perform the numerical analysis of the stress intensity factors whose values, for some special cases, coincide with the data available from the literature. 相似文献
9.
10.
Under the conditions of plane deformation, we study stresses in a piecewise-homogeneous isotropic body near the tip of a mode I crack appearing at the angular point on the boundary of two media. It is assumed that plastic strips (modeled by plastic slip lines) are formed on the boundary of the media. To determine the stresses, we use the Mellin integral transformation and the Wiener–Hopf method. The angular point is a stress concentrator with power singularity and, therefore, immediately after the appearance of lateral plastic strips (zones), a new plastic zone begins to develop from this point. We study the dependence of the power of singularity of stresses on the angle made by the boundary and the elastic characteristics of the media. 相似文献
11.
12.
Sibiath O. G. Osséni Clément Ahouannou Emile A. Sanya Yves Jannot 《International Journal of Thermophysics》2017,38(6):81
This paper presents a study of the hot plate method with two simultaneous temperature measurements, on the heated and unheated faces of a sample to characterize. The thermal properties of polyvinyl chloride, plaster and laterite were considered to be a representative range of building materials. A 1D quadrupolar model was developed to represent the temperature evolution on the two faces over time. Three-dimensional numerical modeling of a quarter of the testing device with COMSOL software allowed defining the domain of the 1D hypothesis validity. The analysis of estimation possibilities of materials’ thermal characteristics, with the developed method, revealed that thermal effusivity can be accurately estimated by using the temperature of the heated face at the beginning of heating. We showed that the simultaneous use of two temperatures enables the estimation of the thermal conductivity with a greater accuracy and over a shorter time interval than using the temperature of the heated face alone. We also demonstrated that under certain conditions (samples with a high ratio of thickness to width) the method with two temperature measurements enabled the estimation of the thermal effusivity and conductivity, while the method with one temperature allowed only the thermal effusivity to be estimated, because of 3D effects. This conclusion was confirmed by experimental results obtained with a mortar sample. 相似文献
13.
We consider specific features of the design of equipment for the investigation of strength and regularities of fracture of sheet structural materials under biaxial tension created by loading specimens by one-sided pressure of the working medium. We propose solutions of several methodical problems connected with testing under high pressures of the working medium which enable one to realize the required modes of cooling of the specimens, decrease the level of fracture energy, and increase the reliability and safety of testing. 相似文献
14.
15.
By using the well-known δ
c
-model, we establish new formulas for the evaluation of the crack-tip opening displacement with regard for a more complicated
interaction of the edges of a model cut in the process zone of the material and determine the dependence of the critical load
on the ratio of the initial crack length to the length of the process zone regarded as constant.
__________
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 41, No. 4, pp. 5–8, July–August, 2005. 相似文献
16.
Materials Science - The solution of the problem of stationary transverse vibration of an orthotropic plate of any shape with the set of holes of any configuration subjected to the action of... 相似文献
17.
18.
Malezhyk М. P. Pidhurs’kyi М. І. Rudyak Yu. А. Fedyshyn N. О. Pidhurs’kyi І. М. Voitovych L. V. 《Materials Science》2019,55(2):260-264
Materials Science - By the method of dynamic photoelasticity, we study the dynamic fracture of structural elements in the form of plates made of transparent composites and weakened by a hole and... 相似文献
19.
为确定金属板在爆炸荷载作用下的塑性区范围,根据爆炸产物膨胀理论,结合金属板的材料性能,推导了一定形状装药与金属板接触爆炸的塑性区域公式。通过化爆试验实测了板的塑性变形范围。比较计算结果与试验结果表明,理论得到的板塑性区范围与试验结果较吻合。 相似文献
20.
Andreikiv O. Ye. Dolins’ka I. Ya. Shtoiko I. P. Raiter O. K. Matviiv Yu. Ya. 《Materials Science》2019,54(5):638-646
Materials Science - We proposed new procedures for the evaluation of the residual service life of main pipelines with surface cracks under the action of a long-term constant gas pressure in gas... 相似文献