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Development of Optimum Proof Testing Method of Structural Ceramics

结构陶瓷最佳验证测试方法的开发

基本信息

批准号：
01850021
负责人：
ICHIKAWA Masahiro
金额：
$ 4.86万
依托单位：
The University of Electro-Communications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01850021/
关键词：
Fine Ceramics Structural Ceramics Proof Test Reliability 信頼性ファインセミラックス

项目摘要

The aim of this research is to develop the optimum method of proof testing of structural ceramics. The optimum method implies such a method by which the highest probability of surviving proof testing is attained under the condition that S_<fmin>*S_d, where S_<fmin> is the minimum strength after proof testing and S_d is the required strength. The principal results of the research are summarized as follows.1. The optimum proof testing method was first studied for the case of uniform stress distribution. It was found that the optimum testing method is to use the maximum unloading rate available and the test load which satisfies S_<fmin>=S_d under this unloading rate.2. The optimum proof testing method was then studied for the case of non-uniform stress distribution. This case Is Important as real machine components are generally subjected to non-uniformly distributed stresses. It was found that the optimum testing method is to use the maximum unloading rate available and the test load whi … More ch satisfies S_<fmin>=S_d at the point of the maximum stress in the component.3. The influence of the K-V relation on the effect of proof testing was studied by means of computer simulation, where K is the stress intensity factor and V=da/dt is the stable crack growth rate. It was found that when the unloading rate is larger than the critical unloading rate, exterpolation of the first region's K-V relation to the second and third regions does not result in substantial error in calculation of the minimum strength after proof testing and the probability of surviving the proof test.4. A method for estimating the critical unloading rate was proposed, and the usefulness of this method was demonstrated experimentally.5. For application of proof testing to ceramic bearing balls, the statistical properties of the ring crack initiation strength and the final fracture strength under crushing load were clarified experimentally. Furthermore, a probabilistic theory for interpreting the experimental results was proposed.6. Proof testing of Si_3N_4 bearing balls was conducted and importance of unloading rate was demonstrated experimentally. Less

本研究的目的是发展结构陶瓷的最佳验证方法。最优方法是指在满足S_<fmin>*S_d（S_<fmin>为验证后的最小强度，S_d为所需强度）的条件下，使验证后的存活概率最大的方法。主要研究结果如下：1.首次研究了应力均匀分布情况下的最佳验证试验方法。研究发现，最佳试验方法是采用现有的最大卸载速率，并<fmin>在此卸载速率下采用满足S_ =S_d的试验载荷.研究了应力分布不均匀情况下的最佳验证试验方法。这种情况很重要，因为真实的机器部件通常承受非均匀分布的应力。试验结果表明，最佳试验方法是采用最大卸荷速率，试验载荷为 ...更多信息 ch<fmin>在构件最大应力点满足S_ =S_d.用计算机模拟的方法研究了K-V关系对验证试验效果的影响，其中K为应力强度因子，V=da/dt为稳定裂纹扩展速率。研究发现，当卸载速率大于临界卸载速率时，将第一区域的K-V关系外推到第二和第三区域，不会导致验证试验后最小强度和验证试验后存活概率的计算出现实质性误差.提出了临界卸载速率的估算方法，并通过实验验证了该方法的有效性.为了应用于陶瓷轴承球的验证试验，通过实验阐明了在破碎载荷下环裂纹起始强度和最终断裂强度的统计特性。此外，还提出了解释实验结果的概率理论.对Si_3N_4轴承球进行了验证性试验，试验证明了卸载率的重要性。少