广东费飘职业故本学院 Guangdong Inatitute of Textile Technology Fiber Properties and Identification 口 Stress-strain curves ■ Hardening point 百 The polymer molecules ardening become more oriented as noint strain increases and the fiber reaches a deformation limit, where the molecules have the highest orientation and (stress) hardening occurs 8
Fiber Properties and Identification Stress-strain curves ◼ Hardening point The polymer molecules become more oriented as strain increases and the fiber reaches a deformation limit, where the molecules have the highest orientation and (stress) hardening occurs. 0 Hardening point
广东费飘职业故本学院 Guangdong Inatitute of Textile Technology Fiber Properties and Identification a Stress-strain curves ■ Failure point a Where the fiber fails a Sometimes not necessary the maximum stress point 口 Depends on definition
Fiber Properties and Identification Stress-strain curves ◼ Failure point Where the fiber fails. Sometimes not necessary the maximum stress point. Depends on definition
广东费飘职业故本学院 Guangdong Inatitute of Textile Technology Fiber Properties and Identification a Stress-strain curves Tenaci city a Stress at the point of rupture a stress at the maximum load a Unit: N/tex, gf/denier
Fiber Properties and Identification Stress-strain curves ◼ Tenacity Stress at the point of rupture. Stress at the maximum load. Unit: N/tex, gf/denier
广东费飘职业故本学院 Guangdong Inatitute of Textile Technology Fiber Properties and Identification a Stress-strain curves Stress at break a Strain or elongation at or tenacity break 口% of strain at the point of rupture. 口 Strain at the maximum load 8 Strain at break
Fiber Properties and Identification Stress-strain curves ◼ Strain or elongation at break % of strain at the point of rupture. Strain at the maximum load. 0 Strain at break Stress at break or tenacity
广东费飘职业故本学院 Guangdong Inatitute of Textile Technology Fiber Properties and Identification Stress-strain curves lork of rupture a Physics: Work= Force Distance=FS a If F= f(s)is not a constant When change of distance As is very small, Fis almost a constant. thus →→△W=F△SOr → therefore:dw=f(5)s → when as→>O W=J=∫( 0 0
Fiber Properties and Identification Stress-strain curves ◼ Work of rupture Physics: Work = Force ´ Distance = F ´ s If F = f(s) is not a constant → When change of distance s is very small, F is almost a constant, thus → w = F s or → when s → 0, dw = f(s)ds → therefore: = = l l W dw f s ds 0 0 ( )