基于区间分析的履带起重机结构非概率可靠性研究

Non-probabilistic reliability study for the crawler crane structure based on the interval analysis

臂架结构作为履带起重机的重要部件,其结构的强度、刚度和稳定性决定了整个起重机的安全性和使用性能。为了预测履带起重机臂架结构的可靠度,采用区间非概率研究履带起重机的可靠性,只需知道不确定参量的界限而不需知道其分布情况,就能求出各功能函数的可靠性指标;将履带起重机臂架的额定起重量、起升载荷偏摆角度、起升冲击系数等不确定参量看成区间变量,建立了以臂架强度、刚度、整体稳定性为失效模式的可靠性分析模型;将区间变量标准化,在标准化区间变量的扩展空间中,按无穷范数度量从坐标原点到失效面的最短距离,以此来判断结构的非概率可靠度。最后,用该模型对现有某型号履带起重机臂架进行了可靠性分析,结果表明,用该方法得到的履带起重机区间非概率可靠度η〉1,符合实际情况。

This paper is aimed to make a comprehensive study of the reliability of the crawler crane so as to identify and define the boundaries of the uncertain parameters on the condition with no need to know its distribution and work out the reliability extent of each function through the interval-based non-probability analysis. And, as a matter of fact, it is first of all necessary to forecast and define the reliability of the boom structure of the crawler crane and its jib structure, for they are an important component of the crawler crane, along with its structural strength, stiffness and stability, on which the safety and performance of the entire machine is relied on. What is more, to establish the boom strength, the stiffness, and the overall stability, it is also of great need to set up a rehability analysis model of failure modes of the rated hoisting weight, deflection angle of lifting load and lifting impact coefficient, with some other uncertain parameters taken as the interval variables. Furthermore, η be taken as a non-probabilistic reliability index of the structure, 0 〈 η 〈 1 should be regarded unsafe in theory; η = 1 when the failure surface were tangent to the set of the basic interval parameters, it should be supposed that, the crane remains in a ＂critical＂ state between safe and unsafe; η 〉 1 was considered safe. And, then, the boom of the crawler cranes should be analyzed with the non-probabilistic reliability of some certain currently used the calculation method of interval non-probabilistic reliability. The successful application of the aforementioned method may lead us to prove that the strength, stiffness and stability of the interval non-probabilistic reliability of the crane and the results of the non-probabilistic interval are well in accord with the objectively existing actual situation. The abovementioned research results can thus be expected to provide some safety measures of the jib structure based on the reliability calculation and the other large-scaled complex mechanical engineering design principles and therefore qualified to provide its own valuable reference in the field.