Experimental Study On Damage Properties Of Adhesive-rivet Hybrid Repair Of Composite Materials

In the practical application of composite materials,there are significant advantages of multiple indexes,which makes such materials widely used in many fields.However,in the actual processing,it is very easy to cause problems such as loose,crack and pore.The impact of load,impact and fatigue on composite materials in service may lead to defects and damage of the materials.Serious damage may lead to comprehensive damage effect of the materials and further bring about structural safety and other problems.Therefore,the damage detection of such composite materials can ensure the safety of the structure.Therefore,in this paper,the composite aircraft skin,design,manufacture and complete the supporting tensile test.Combining the wavelet packet decomposition and spectrum analysis of acoustic emission technology,the damage mode corresponding to the key frequency band of the signal was found.The details are as follows:(1)test pieces with different repair methods of intact plate,60 mm and 30 mm were used to treat the test pieces by static tensile test in the actual experimental process.Furthermore,the detailed information of failure strength,failure mode and damage morphology of the test parts can be further compared.Through such information,it can be found that the repair method of adhesive riveting mixed repair can bear more load in the tensile test,and the failure position is at the edge of the outermost row rivet hole perpendicular to the loading direction.Different from riveting repair,the fracture position of riveting repair is along the edge of the damaged hole perpendicular to the loading direction.The fracture patterns of the fracture fibers were similar between the two different repair methods,and the effect of different damage holes on the fracture fibers was not obvious.(2)compare the strain of 8 different parts of the test piece with intact plate,60 mm and 30 mm aperture with different repair methods,and the results show that: Bonding repair damage to the hole of strain growth compared with the other seven largest strain,plastic rivet repair the outside damage holes near the edge of the rivet strain increase,the biggest by the fracture images can be seen that the strain's biggest point is the fracture location,thus it can be seen on bonding repair damage to the hole position to produce stress concentration,plastic rivet repaired the outside rivet hole near the edge position to produce the phenomenon of stress concentration and 60 mm with a 30 mm damage after repair glue riveting mixed plate and strain distribution rule.(3)using acoustic emission technology characteristic spectrum combining SEM fracture of tensile test image combination analysis injury patterns and evolution characteristics of carbon fiber composite materials,by combining the carbon fiber composite material damage features,for getting the signal of time domain and frequency domain characteristic of research in detail,the key to determine the signal frequencies corresponding to the damage.Sound emission is an important tool with high feasibility and good processing effect.