Interval Analysis Method of a Powertrain Mounting System with Uncertain Parameters

Author(s):  
Pengfei Chen ◽  
Yunqing Zhang ◽  
Gang Qin ◽  
Jinglai Wu
2006 ◽  
Vol 03 (02) ◽  
pp. 229-244 ◽  
Author(s):  
Y. T. ZHOU ◽  
C. JIANG ◽  
X. HAN

In this paper, the interval analysis method is introduced to calculate the bounds of the structural displacement responses with small uncertain levels' parameters. This method is based on the first-order Taylor expansion and finite element method. The uncertain parameters are treated as the intervals, not necessary to know their probabilistic distributions. Through dividing the intervals of the uncertain parameters into several subintervals and applying the interval analysis to each subinterval combination, a subinterval analysis method is then suggested to deal with the structures with large uncertain levels' parameters. However, the second-order truncation error of the Taylor expansion and the linear approximation of the second derivatives with respect to the uncertain parameters, two error estimation methods are given to calculate the maximum errors of the interval analysis and subinterval analysis methods, respectively. A plane truss structure is investigated to demonstrate the efficiency of the presented method.


Author(s):  
Jie Hong ◽  
Jun Wang ◽  
Meng Chen ◽  
Yanhong Ma

The support stiffness and connecting structure stiffness change with different assembly conditions and operating conditions. The phase and amount of rotor unbalance in different operating cycle changes due to wear of blade tip and connecting structures in different working cycles. These parameters which have significant effect on rotordynamics are “uncertain but bounded”, in another word, the distributions of the parameters are unknown, but the intervals of uncertain parameters are always got easier. An interval analysis method, which solves the dynamic response with these uncertain parameters, has presented. Based on interval mathematics and modal superposition method, interval analysis method simplifies the uncertain parameters to interval vectors so that it can get the intervals within which the dynamic response varies when less information of structure is known. The interval analysis method is efficient under the condition that probability approach cannot work because of small samples and sparse statistics characteristics. The formulation of rotor dynamic response using interval modal superposition analysis method is formulated. A numerical example of comparison between interval analysis method and Monte Carlo method is given, and the results illustrate the interval analysis method.


Author(s):  
Yanhong Ma ◽  
Peng Cao ◽  
Jun Wang ◽  
Meng Chen ◽  
Jie Hong

The support stiffness and connecting structure stiffness which has significant effect on rotordynamics change with different assembly conditions and operating conditions. For example, the squeeze film stiffness changes with different film force, and the elastic support stiffness changes with different temperatures. These parameters are “uncertain but bounded”, in another word, the distributions of the parameters are unknown, but the intervals of the uncertain parameters are always got easier. An interval analysis method, which solves the rotordynamics with these uncertain parameters, is presented. Based on interval mathematics and perturbation method, interval analysis method simplifies the uncertain parameters to interval vectors so that it can get the intervals within which the rotordynamics varies when less information of structure is known. The interval analysis method is efficient under the condition that probability approach cannot work because of small samples and spare statistics characteristics. The formulation of natural frequencies of rotor using interval perturbation analysis method is formulated. A numerical example of comparison between interval perturbation method analysis and monotonic method is given. The rotordynamic analysis of a turbofan rotor is performed with this method, and the test data validates the numerical results.


2020 ◽  
Vol 475 ◽  
pp. 115258 ◽  
Author(s):  
Hai B. Huang ◽  
Jiu H. Wu ◽  
Xiao R. Huang ◽  
Wei P. Ding ◽  
Ming L. Yang

2006 ◽  
Vol 324-325 ◽  
pp. 971-974 ◽  
Author(s):  
Chang Hong Liu ◽  
Hu Huang

With the concepts of the confidence interval, a random parameter can be transformed into an interval number in the mesco ductile fracture. Hence analyses of the random isolated void model can be used in the interval analysis method. Based on the macro- and mesco-experimental results of four steels, 30CrMnSiA, 40CrNiMoA, No.45 and No.20, the probabilistic fracture characteristics of the four steels are given. Finally the interval isolated void models in the four steels are discussed.


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