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基于多试样法的PVC塑料J-R阻力曲线的简便测量方法
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作者 黄建伟 唐鹏飞 +3 位作者 潘栋 石拓 莫淑蓓 李颢旭 《压力容器》 北大核心 2024年第7期25-31,共7页
获得PVC材料的J-R阻力曲线以及断裂韧度J_(IC)的难点在于裂纹扩展量Δa的测量,传统染色处理以及三维测量等方法过程复杂且测试成本高。由于塑料的易切割性,可以简化Δa的测量过程。因此,基于多试样法,提出根据规范的测点要求对加载后的... 获得PVC材料的J-R阻力曲线以及断裂韧度J_(IC)的难点在于裂纹扩展量Δa的测量,传统染色处理以及三维测量等方法过程复杂且测试成本高。由于塑料的易切割性,可以简化Δa的测量过程。因此,基于多试样法,提出根据规范的测点要求对加载后的试件沿着裂纹纵向切割成若干片、再通过工业电子显微镜测量每个切割片上的裂纹长度,从而获得Δa的二维测量方法。通过GB 21143—2014和ASTM D6068-10两个标准,应用该方法均能获得相对一致的J-R阻力曲线和J_(IC)值,测试结果有效且准确。其中根据GB 21143—2014获得PVC的J_(IC)值为8.03 kJ/m^(2),J-R阻力曲线拟合方程的系数为9.93,指数为0.15;根据ASTM D6068-10获得PVC的J_(IC)为8.31 kJ/m^(2),J-R阻力曲线拟合方程的系数为12.7,指数为0.3;表明ASTM D6068-10获得PVC的断裂韧度J_(IC)值和拟合方程的系数、指数均大于GB 21143—2014。由于PVC材料与金属材料性能的差异,得出ASTM D6068-10更适用于测试PVC材料的J-R阻力曲线和J_(IC)值的结论。该方法将传统的裂纹染色处理和三维测量等复杂操作简化为切片和二维测量,简化测量过程,降低了测量成本,可普及应用于塑料断裂韧性的测量。 展开更多
关键词 J-R阻力曲线 断裂韧度J_(IC) 裂纹扩展量 多试样法 二维测量方法
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Residual life estimation based on bivariate Wiener degradation process with measurement errors 被引量:12
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作者 王小林 郭波 +1 位作者 程志君 蒋平 《Journal of Central South University》 SCIE EI CAS 2013年第7期1844-1851,共8页
An adaptive method of residual life estimation for deteriorated products with two performance characteristics (PCs) was proposed, which was sharply different from existing work that only utilized one-dimensional degra... An adaptive method of residual life estimation for deteriorated products with two performance characteristics (PCs) was proposed, which was sharply different from existing work that only utilized one-dimensional degradation data. Once new degradation information was available, the residual life of the product being monitored could be estimated in an adaptive manner. Here, it was assumed that the degradation of each PC over time was governed by a Wiener degradation process and the dependency between them was characterized by the Frank copula function. A bivariate Wiener process model with measurement errors was used to model the degradation measurements. A two-stage method and the Markov chain Monte Carlo (MCMC) method were combined to estimate the unknown parameters in sequence. Results from a numerical example about fatigue cracks show that the proposed method is valid as the relative error is small. 展开更多
关键词 residual life performance characteristics bivariate Wiener process Frank copula MCMC method
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Development of 2D Temperature and Concentration Measurement Method Using Tunable Diode Laser Absorption Spectroscopy 被引量:7
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作者 Yoshihiro Deguchi Daisuke Yasui Akira Adachi 《Journal of Mechanics Engineering and Automation》 2012年第9期543-549,共7页
Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is int... Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is intrinsically a point temperature measurement method and noncontact 2D temperature distribution cannot be attained by thermocouples. Recently, as a measurement technique with high sensitivity and high response, laser diagnostics has been developed and applied to the actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on a Computed Tomography (CT) method using absorption spectra of water vapor at 1388 nm. It has been demonstrated that the method has been successfully applied to engine exhausts to measure 2D temperature distributions. 展开更多
关键词 2D temperature measurement tunable diode laser absorption spectroscopy CT (computed tomography) engine exhausts.
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