Research On Mechanical Properties Of A Composite Laminates In Hygrothermal Condition

Carbon fiber reinforced composite laminates is one of the most commonly materials used in aerospace vehicles as a new and high-performance composite laminates.However,polymer gets aging easily under the influence of environmental factors,and hygrothermal environment is one of the most serious conditions.So the design departments and the user departments are particularly concerned about the damage of the composite laminates in hygrothermal condition and the changes of mechanical properties.It is the precedent condition of taking composite laminates into application.The moisture absorption properties of composite laminates of a certain type of XXX in hygrothermal condition are studied in this paper.The mechanisms of hygrothermal aging of the composite laminates in different hygrothermal conditions are researched by IR and SEM.The mechanical properties of warp tensile,weft tensile,warp compression,weft compression,longitudinal-transverse shear,warp bend,weft bend,open hole tensile,open hole compression,bearing strength and dynamic mechanics are tested.The fracture characters of the composite laminates are analysed.The main works of the paper are shown as following.First,water-sorption experiments of standard samples,warp tensile samples,weft tensile samples,warp compression samples,weft compression samples,longitudinal-transverse shear samples,warp bend samples,weft bend samples,bearing strength samples and dynamic mechanics samples are performed in the temperature of 71? till the samples reaching to moisture balance.Water-sorption experiments of samples of open hole tensile and open hole compression are performed at temperature of 71? and condition of relative humidity of 85%.Second,in order to investigate the changes of the surface morphology and chemical composition,the surface morphology and the microstructure of the composite laminates in different hygrothermal conditions are observed by IR and SEM.Besides,static mechanics of wet specimens are tested at temperatures of 20?,71 ?,93?,116?,132? and static mechanics of dry specimens are tested at temperatures of 20?,93 ?.Dynamic mechanics of dry specimens and wet specimens are tested by DMA.At last,in order to investigate the influence of hygrothermal environment on mechanics performance of the composite laminates,the changes of mechanics performance of the composite laminates in different hygrothermal conditions are analysed.The fracture mode of specimens in different hygrothermal conditions and expound elaborate of failure mechanism are analysed.The basic failure modes of the composite laminates are summaried.