摘要：
Through the differentiating and integrating process, a mathematical model for tempering time effect on quenched steel was derived based on the attribute of state function and the general equation of Hollomon parameter, which correlates the tempering hardness with the tempering time at different tempering temperature. Using the established model, the linear relationship between the tempering hardness and the tempering time in logarithm was proved theoretically, and the tempering hardness for various tempering time was reduced to the measurement and calculation of a hardness experiment tempered for 1 h at different tempering temperatures. Moreover, the hardness of steel 42CrMo and T8Mn tempered for various times at 200 similar to 600 similar to C was calculated using this method. The predicted results are in good agreement with those of the available experiments.
作者机构：
[郑晓; 林国祥; 王少梅; 李智] Department of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 430023, China;College of Logistic Engineering, Wuhan University of Technology, Wuhan 430062, China
通讯机构：
Department of Mechanical Engineering, Wuhan Polytechnic University, China
摘要：
It is necessary to model and simulate the time histories of the road for ride dynamics of a vehicle subjected to the stochastic road excitation. This paper focuses on the mathematical model, algorithm design and simulation realization of road in time domain. The methods converting the frequency domain model of road irregularity to the time domain model were analyzed and the correlations between vehicle wheels and between tracks were taken into account in modeling the numerical road. Three main algorithms, harmony superposition, white noise filtration, and Inverse Fast Fourier Transform (IFFT) based on road power spectral density (PSD), were designed and integrated as a system of road simulation constructed on the MATLAB software platform. For the simulation to be as realistic as possible, several important aspects, including the bi-lateral track relation in time domain, the improvement of simulation algorithm and the integration of the methods were emphasized. The simulation example demonstrates that the applied methods are general and efficient, and the resulting time domain road agrees fairly well with the reality.
