模糊可靠度计算的两类模式

为使模糊可靠度的计算更加接近和符合实际 ,合理地选取隶属函数来客观地描述模糊抗力 ,提出将模糊抗力的隶属函数选取偏小型和中间型两大类。据此可将模糊可靠度的计算划分为偏小型隶属函数和中间型隶属函数两类模式。对于人为规定的各种许用值 ,如许用挠度值、许用磨损量等 ,根据经验公式确定它们的大小时往往有一个区间或一个极限值 ,宜用偏小型隶属函数描述 ;对于零件的各种强度值 ,如抗拉强度、抗压强度、接触强度等 ,实际中往往只能确定其近似的均值 ,宜用中间型隶属函数描述。给出了按两类模式计算零件模糊可靠度的方法和有关公式 ,并给出了计算实例。

Two kinds of patterns for calculating fuzzy reliability

To make the calculation of fuzzy reliability closer to and accorded with the actual conditions, it is quite important to select reasonable membership function which describes objectively fuzzy resistance. It is proposed to divide the membership function of fuzzy resistance into two kinds of patterns: deflection minor type and middle type. Thereby the calculation of fuzzy reliability can be divided into two kinds of patterns: deflection minor type and middle type membership function patterns. As for the factitiously specified allowable values, such as allowable deflection, allowable amount of wear, and so on, their magnitudes, which are confirmed on the basis of empirical formula, often have an interval value or a limit value, therefore they can be described suitably by minor type membership function; As for various strength values of parts, such as tensile strength, compression strength, contact strength and so on, their magnitudes, which are often confirmed only by approximate mean, can be described suitably with middle type membership function. The method and relevant equations for calculating the fuzzy reliability of parts by above-mentioned patterns are offered, and examples of calculation are given.