ABSTRACT
Summary I n the i n t r o d u c t i o n g e n e r a l problems a re d i s c u s s e d about the c o n s t i t i t u t i v e laws of metals i n connection w i t h computer aided a n a l y s i s of j o i n t s , components or s t r u c t u r e s as regards t h e i r p l a s t i c , f a t i g u e and f r a c t u r e behaviour, p a r t i c u l a r l y the problem of the d u c t i l i t y and c o n s t r a i n t e f f e c t s . Then the s i g n i f i c a n c e of the t r u e f r a c t u r e s t r e s s and s t r a i n obtained w i t h the simple t e n s i o n t e s t i s emphasized. These a r e p a r t i c u l a r l y important i n connection w i t h the f r a c t u r e mechanics parameters f o r c r a c k i n i t i a t i o n and propagation by monotonic and c y c l i c l oading.
