Transient calculation of temperature field and stress field for high-speed electric multiple units brake disc

For the high-speed electric multiple disc brake,as the disc temperature rises sharply during braking,the expansion of the brake disc heat generates heat stress and it causes the braking disc to fail at last.On the basis of heat conduction theory,variational principles in elasticity and thermal stress theory,heat conduction,heat convection and radiation heat transfer produced in each interface and heat stress generated by the expansion of the brake disc heat are analysed.According to the actual dimension of the braking disc,a 3-dimentional cycle-symmetric transient model of brake disc was established.Considering the impact due to the change of elastic modulus,specific heat,thermal conductivity,thermal expansion coefficient and poisson ratio over temperature in virtual simulation process and by means of large-scale finite element software ANSYS,the braking process of the brake disc was simulated,and the temperature and stress distribution in the braking discs was calculated and verified by the test.The simulation results indicate that brake disc reaches the max temperature 416 ℃ at 40 s and reaches the max stress 651 MPa at 60 s after starting at the speed of 200 km/h during emergency braking of high-speed electric multiple,and the designing disc brake can meet the strength requirement.