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41.
冲蚀磨损与冲蚀、空蚀交互磨损的对比研究 总被引:1,自引:0,他引:1
基于计算流体力学(computational fluid dynamics,CFD)方法,数值对比研究了在模拟水轮机工况中不同转速时,冲蚀与冲蚀、空蚀交互作用时,转盘表面的流场(压力场、流体浓度分布),然后在转盘式磨损装置上,进行了汽液固三相冲蚀与空蚀交互磨损试验.结果表明:对于冲蚀磨损来说,随着转速增加,压力增大,在冲蚀作用下加入空蚀磨损,压力增高,磨损加剧;而对于交互磨损来说,随着转速增加,转盘表面的空蚀磨损区域从空化孔附近开始沿着转盘旋转的反方向偏移,并且磨损程度加剧;数值计算的气泡较多且压力梯度较高区域和试验转盘磨损区域基本一致,数值计算结果和试验结果吻合得较好. 相似文献
42.
采用J积分对沥青混合料抗裂性能进行评价 总被引:2,自引:0,他引:2
沥青混合料是一种由集料、胶浆和孔隙组成的非均质材料,一般被认为是一种粘弹性材料,其力学行为介于弹性和塑性之间,采用弹塑性断裂力学更适合评价沥青混合料的抗裂性能.J积分理论可以避开分析裂纹尖端附近复杂的应力应变场,物理意义明确,可以有效的评价沥青混合料的抗裂性能,断裂韧度JC可以很方便的采用预切缝的半圆弯拉试验直接获得.为了评价材料本身特性对断裂韧度JC影响,在MTS试验系统上进行了3种级配的沥青混合料的断裂韧度试验.采用基于数字图像处理技术的有限元方法对半圆弯拉试验进行了模拟,并将数值模拟的结果与试验的结果进行了对比分析.结论表明,断裂韧度JC可以作为一有效的评价沥青混合料抗裂性能的指标. 相似文献
43.
44.
IntroductionThenumericalsimulationoftheevolutionaryhistoryofthebasinisconductedacordingtothemechanismofpetroleumgeologyandmec... 相似文献
45.
46.
江福汝 《应用数学和力学(英文版)》1982,3(5):683-695
In this paper we consider the nonlinear and unsymmetrical bendings of annular and circular thin plates under various supports. The uniformly valid asymptotic solutions have been derived by means of the perturbation method presented in [7]. 相似文献
47.
剪胶接结构的混合模式断裂分析 总被引:1,自引:0,他引:1
给出了Goland-Reissener型剪接结构的J积分表达在被粘物体小转角和胶层很薄的假设下与路径无关。J积分代表胶层厚度与胶层内最大能量密度的乘积。对单剪接接头,本文计算了裂纹在胶层内和界面上两种情况下的局部I型和Ⅱ型应力强度因子之比,即局部载荷相角,从而给出了单剪接接头的断裂判据。 相似文献
48.
In this paper, we focus on the tests for covariance matrices in panel data model with interactive fixed effects. For the problem of testing identity and sphericity of covariance matrices, we first propose test statistics based on the estimators of the trace of covariance matrices. Under both the null hypothesis and the alternatives, we establish the asymptotic distributions of the proposed test statistics under some regularity conditions, and we further show that the proposed tests are distribution free. Subsequently simulation studies suggest that the proposed tests perform well under the high dimensional panel data. 相似文献
49.
A unique set of double-edge notched tension specimens of a Polyethylene Terephthalate Glycol-modified film was tested in mode I, plane stress. The load was registered on a universal testing machine. The displacements, ligament lengths, and video frames were recorded by a Digital Image Correlation system. With these registered data, the essential work of fracture, J-integral, and crack tip opening displacement (CTOD) fracture concepts have been applied. The onset of crack initiation was through a complete yielded ligament. The analysis showed that the intrinsic specific work of fracture, we, is the specific energy just up to crack initiation, which is an initiation value. we has both a coincident value and the same conceptual meaning as Jo, the J-integral at the onset of crack initiation. The relationship between Jo and CTOD is also determined. The influence on the notch quality when the specimens were sharpened by two different procedures, femtosecond laser ablation and razor blade sliding, was analysed in detail. 相似文献
50.
Alain C. Vaucher Moritz P. Haag Markus Reiher 《Journal of computational chemistry》2016,37(9):805-812
Real‐time feedback from iterative electronic structure calculations requires to mediate between the inherently unpredictable execution times of the iterative algorithm used and the necessity to provide data in fixed and short time intervals for real‐time rendering. We introduce the concept of a mediator as a component able to deal with infrequent and unpredictable reference data to generate reliable feedback. In the context of real‐time quantum chemistry, the mediator takes the form of a surrogate potential that has the same local shape as the first‐principles potential and can be evaluated efficiently to deliver atomic forces as real‐time feedback. The surrogate potential is updated continuously by electronic structure calculations and guarantees to provide a reliable response to the operator for any molecular structure. To demonstrate the application of iterative electronic structure methods in real‐time reactivity exploration, we implement self‐consistent semiempirical methods as the data source and apply the surrogate‐potential mediator to deliver reliable real‐time feedback. © 2015 Wiley Periodicals, Inc. 相似文献