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11.
This paper presents a semianalytical method for the prediction of interlaminar stresses and displacements near the free edges and ply cracks in general angle-ply laminates subjected to biaxial extensions and/or in plane shear deformation. The method is based on a state space representation of the three-dimensional equations of elasticity. Numerical solutions are obtained by using layer refinement in the through thickness direction and Fourier series expansion in the other directions. By this approach, an angle-ply laminate may be composed of an arbitrary number of monoclinic layers and each layer may have different material property and thickness. This method guarantees continuous fields of all interlaminar stresses across interfaces between material layers. Numerical results are compared with those obtained from other methods. It is found that the theory provides a satisfactory approximation to the stress singularities near the free edges and ply cracks. Numerical solutions for antisymmetric laminates under extension and general laminates under shearing are new in the literature and can be used as benchmarks for validating new models. 相似文献
12.
本文通过对压电量测系统等效电路图的逐步简化,得出矩形脉冲信号的漏电方程;并对系统在各种情况下的时间常数,漏电相对误差进行了计算,最后就系统在校准和现场测试中经常碰到的几种情况,进行了定量估算,从而解决了压电量测系统在使用中的一些具体问题。 相似文献
13.
从冷却曲线上相变段倾角最小原则出发,研究了新型激冷剂的配比与热分析法检测铸铁成分精度的关系,实验结果表明,能使相变段倾角最小的成分配比,也能提高对铸铁成分的热分析和检测精度。 相似文献
14.
长25-29井在完井阶段通井过程中发生粘附卡钻事故,在处理卡钻过程中又发生卡套铣筒、井漏、溢流等事故及复杂情况。通过对井下情况的认真分析,采取先堵漏后循环再解卡的处理方案,顺利地解除了该次卡钻事故,大大地减少了经济损失。 相似文献
15.
The main purpose of this paper is to find the mixed-mode stress intensity factors of composite materials using the crack opening displacement (COD). First, a series solution of the composite material with a crack was used to evaluate COD values. Then, the least-squares method was used to calculate mixed-mode stress intensity factors. This algorithm can be applied to any method that generates or measures COD values. The major advantage of this method is that COD values very near the crack tip are not necessary. Both finite element simulations and laboratory experiments were applied to validate this least-squares method with acceptable accuracy if the even terms of the series solution are removed. 相似文献
16.
Erian A. Armanios 《Canadian Metallurgical Quarterly》1991,4(2):216-235
A validation of the delamination analysis models developed in a companion paper is provided through comparisons of predictions with finite‐element and elasticity solutions. The models are applied to the analysis of composite compression specimens reinforced with end tabs. An elasticity solution for the gage section of the specimens is developed. A comparison of the characteristic roots shows that the predictions of the models include the material and geometric parameters that control the behavior, and the roots corresponding to the basic stretching and bending modes are accurately predicted. The stress distribution at the interface between tabs and specimen is in good agreement with a finite‐element simulation. The interlaminar shear and peel stresses show an exponential increase with a maximum intensity at the free edges of the tabs. The behavior of previously tested specimens is explained; and practical guidelines for specimen design are provided to avoid unwanted extraneous modes of failure. The influence of the deformation modes associated with each model is investigated. An assessment of the accuracy and level of complexity is presented. 相似文献
17.
斯新中 《石油化工设备技术》1996,17(4):1-3
根据十万立方米浮顶油罐罐壁板应力测试的实测结果,运用应力分析程序,对罐壁板应力分布情况进行了分析和比较,通过调整罐壁板的厚度,使新设计储罐的罐壁板应力分布更加均匀、合理。 相似文献
18.
This paper addresses the aging behaviour of NiCr/CuNiMn/NiCr triple layers on Al2O3 ceramics at temperatures up to 200°C for film thicknesses d0.5 μm. Investigations of the film structure and the increase of resistance and its temperature coefficient during the annealing process and studies of the dependence of this aging drift on both the film thickness and the storage temperature have been carried out. Furthermore, the film stress and the effect of substrate bending on resistance have been measured. The results can be explained by the irregular film structure (columns and small bridges between them), which causes stress and current concentrations as well as local creeping, cracking and oxidation processes in the micro-bridges. They are compared with such for structurally homogeneous films on silicon wafers. 相似文献
19.
在分析转向柱管花键部位应力集中情况的基础上,通过对某厂生产的转向柱管扭转破坏的试验研究,得到如下结论:①转向柱管的承载能力与其外花键齿与方向盘中心内花键齿之间的非接触区长度有关,以花键端部过渡圆弧的直径大小为宜;②安装方向盘总成时所施加在安装螺母上的拧紧力矩在70N.m左右时,转向柱管的承载能力最大。 相似文献
20.
A simple measuring procedure for low concentrations of H2 and H2S (at the level of ppm fractions) above the surface of water by using sensitive gas analyzers is suggested. The procedure is easily accomplished in conditions outside the laboratory (under field conditions). 相似文献