Tensoes residuais

Measurement of Residual Stress Distribution by the Incremental Hole-Drilling Method
A. Niku-Lari* J. Lu** and J.F. Havenot** * II'IT-International, 40 Promenade Marx Dorrnoy, 93460 Gournay sur Mame (France) ** :TIM, ' 52 Av. Fdlix Louat, 60304 Senlis (France)

INDUSTRIAL S M A Y U MR The h o l e - d r i l l i n g method i s w i d e l y u s e d f o r t h e measurement o f r e s i d u a l s t r e s s e s i n m e c h a n i c a l components. R e c e n t d e v e l o p m e n t s h a v e shown t h a t s t r a i n s m e a s u r e d on t h e s u r f a c e d u r i n g a n i n c r e m e n t a l d r i l l i n g c a n b e r e l a t e d t o r e s i d u a l - s t r e s s d i s t r i b u t i o n . R e s e a r c h e r s , i n t ' e r n a t i o n a l y , have proposed d i f f e r e n t methods of c a l i b r a t i o n which l e a d t o r e s u l t s o f v a r y i n g d e g r e e s of accuracy.
A new method o f The p r e s e n t p a p e r d i s c u s s e s t h e d i f f e r e n t a p p r o a c h e s u s e d . c a l i b r a t i o n i s p r o p o s e d and i t i s shown how t h e f i n i t e e l e m e n t a n a l y s i s c a n b e u s e d f o r t h e d e t e r m i n a t i o n o f t h e c o r r e l a t i o n c o e f f i c i e n t s . The v a r i a t i o n o f t h e s t r a i n s measured on t h e s u r f a c e f o r e a c h increment i s due, f i r s t l y t o t h e r e s i d u a l s t r e s s e s i n t h e l a y e r and s e c o n d l y , t o t h e change of t h e h o l e geometry. Most a u t h o r s d o n o t c o n s i d e r t h e l a t t e r a s p e c t , b u t t h e p r e s e n t l y r e p o r t e d results sh t h a t t h i s causes a s i g n i f i c a n t e r r o r i n t h e experimental data. The f i n i t e - e l e m e n t method h a s b e e n u s e d f o r t h e c o m p u t a t i o n o f t h e c o e f f i c i e n t s f o r a l l t y p e s o f s t r a i n - g a u g e r o s e t t e s when t h e h o l e d i a m e t e r i s p r e - d e t e r m i n a t e d .

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