Abstract: Through calculation and analysis,we obtained the general expression of the critical pressure during longitudinal and transverse bending of bars,derives,on the basis of Euler stress,the calculating formula of critical temperature and length during longitudinal and transverse bending of bars by the reliabilty theory.It provides a new analysis method for the calculation of thermal buckling problems of bars,and a base for stability analysis of heating t ransportation pipelines.

Key words: longitudinal and transverse bending, thermal buckling, critical temperature, reliability theory