随机振动下小子样机械产品可靠性评估

Reliability evaluation for less sub-samples of mechanical product under random vibration

针对机械产品使用寿命一般比较长,用于振动试验的产品数量必须很少的特点,提出一种基于经典方法、通过增大产品承受的应力,并结合应力-强度干涉计算,建立适合极小子样产品的可靠性评估方法。研究了过载随机振动试验的实现手段。讨论了过载试验中确定过载系数上限的问题。针对某一高可靠性产品,利用随机振动试验获得薄弱部位的应力响应规律,经可靠性评估表明,如果提高输入功率谱密度约108%,只需选取4～5件进行可靠性试验即可。该方法对试验费用昂贵,小子样产品的可靠性评估,具有工程实用价值。

Aiming at the special features of a commonly fairly long service life of mechanical product, and the product used for vibration test has to be less in quantity, a kind of classical method has been put forward, by means of increasing the product's bearing stress, and combining with the interference calculation of stress-strength to establish a method suitable for reliability evaluation on extremely less sub-sampled products. The means of realization for overloading random vibration test was studied. The problems for determining the upper limit of overload coefficient were discussed. Directed against a certain high reliability product, the stress response law of the thin and weak part was obtained by means of random vibration test. It is indicated through reliability evaluation that it is available to carry out the reliability test by choosing only 4~5 components if the spectral density of inputting power has been increased to about 108%. This method possesses practical value in engineering for the reliability evaluation upon less sub-sampled product with an expensive testing cost.