Question

1.3 Prove that according to the Voce equation for the stress-strain curve, the true stress and the natural strain at the onset of instability in uniaxial tension are Сп _In[m(1 + n)] 0 E = 1 + 1

Answer 1

Solution: - roce equation can be coritten as 5= C (1-mene According to roce equation, the instability condition is de se { [-me)} - = cm nehe = n(C-6) and the onset of instability comesponds to ncc-o)=o or o= Ch 1+1 o n c ith Hence, ne cmne c m n -ncc-6) - n.cc-o) cmn = nCc-6) ene one = cmn (coo) cm C-6 .

ә = х р х 1 - Ш х 1 тхо — \ а +, 4- - х е - m (I-Фр) Сен ТІь m ( 1-у) J, m (1) 701