An investigation was carried out about
damage mechanism of Cu
Pm friction material under passive confined pressure and one
dimensional strain state.
Dynamic compression test were made at strain rate 10 2～10 3/s by split Hopkinson Pressure Bar,bullet speeds are 4～16m/s,specimen size is 12×6,and the results show when one dimensional strain state:(1)the material display a tendency toward negative strain rate effect.The damage weakening mechanism resulted from a rate dependent evolution of cracks are that initial crack and porous material absorb most energy at short time under dynamic
loading ,which make the material strength descending ,sometimes the harden grain are damaged, but the adiabatic heating shear behavior don’t take place;(2)the initial crack and porous develop quickly under dynamic loading ,and deform the multi source crack and cavity pool at big range .The SEM morphology show that material damage model is dynamic invalidation .Under quasi one dimensional strain state, the material have strengthen strain rate effect at the same strain rate as though the properties of the motel material at static state ,sometimes the material’s density become bigger,development of crack is lower from SEM analysis.
More summaries about the Damege Mechanism of Cu Powder Metallurgy(PM) Friction Material under Dynamic Loading