| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method and a device for estimating fatigue strength based on a finish which can easily evaluate a fatigue life in a low cycle region of a machine component having any finish. <P>SOLUTION: A modified goodman diagram for a reference material is generated. Meanwhile, the relational expression between fatigue strength and hardness is obtained and the relational expression between fatigue strength and roughness is also obtained. After the residual stressσ<SB POS="POST">res</SB>, hardness Hv and roughness Ra of a surface processing layer of a machine component are measured, a hardness coefficientαis obtained from the relational expression between fatigue strength and hardness using the hardness Hv, and a roughness coefficientβis also obtained from the relational expression between fatigue strength and roughness using the roughness Ra. Then, the residual stressσ<SB POS="POST">res</SB>is inputted to the modified goodman diagram as well as average stressσ<SB POS="POST">m</SB>acting on the machine component, and the fatigue strengthΔε<SB POS="POST">t</SB>when the residual stress is acting is obtained. The fatigue strength of the machine componentΔε<SB POS="POST">t,wrk</SB>is obtained by multiplying the obtained fatigue strengthΔε<SB POS="POST">t,res</SB>when the residual stress is acting by the hardness coefficientαand the roughness coefficientβ. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
