Prediction of overall tension behavior of short fiber-reinforced composites

The bridging stress of _bers along the crack surface plays an important role in analyzing the tension behavior of short or long _ber!reinforced composites[ This paper uses the inclusion theory to obtain the expression of bridging stress for short _ber reinforced composite "SFRC#[ A simpli_ed model with period! ically distributed _bers is proposed to estimate the average _ber spacings[ The total fracture resistance is calculated as an energy summation including interface debonding energy dissipation\ frictional sliding work between _bers and matrix\ strain energy increment of _bers and matrix[ The bend over point "BOP# stress is calculated by this fracture resistance[ The necessary conditions of the _bers and matrix for the multiple cracking in SFRCs are discussed and the expression of ultimate external stress is derived[ The critical _ber volume fraction for the strain hardening response is determined by an iteration method[ In the meanwhilethe average spacing between two short _bers is proposed by a periodical distribution assumption[ The theoretical prediction is compared with experimental data