Research On Automatic Placement Of Embedded Defects And Tensile Properties Of Composite Materials

Automatic fiber placement（AFP）process can effectively produce large compositecomponents,but some defects occur due to the section at the end of the tow.The existence of defects will cause great changes in the strength and stiffness of composite components,and even become the initial point of failure of composite components.Therefore,it is of great significance to study the influence of typical defects of automatic wire laying on the mechanical properties of components.The main research contents of this project are as follows:（1）When studying the influence of automatic placement of the gap defect Angle atthe end of the filament on the tensile properties of the laminate,the gap defect Angle at different end angles of the filament was set to±30°,±45°,±60°,30°,45°,60°and 90°respectively in the direction of 0°fiber layup and 90°fiber layup.When the defect is set in the direction of 0°fiber layup,the order of the sample layup is[（90°/0°）₅/90°];when the defect is set in the direction of 0°fiber layup,the order of the sample layup is[（0°/90°）₅/0°].The tensile test and data analysis of the samples showed that the tensile strength was the highest when the Angle of the imbedding defect was±30°in the direction of 0°,the ratio of the tensile strength to the intact sample reached 28.48%.When the fiber lay was embedded with defects in the direction of 90°,the tensile strength was the highest when the Angle of the embedded defect was 90°,and the ratio of the tensile strength to the intact sample reached 90.89%.（2）When studying the influence of automatic placement of the overlap defect angle at the end of the filament on the tensile properties of the laminate.The samples were tested and analyzed in the tensile test.The experimental data showed that when the fiber lay was embedded with defects in the direction of 0°,the tensile strength was the highest when the angle of the embedded defects was 30°,and the tensile strength ratio reached50.71%compared with the intact samples.When the fiber lay was embedded with defects in the direction of 90°,the tensile strength was the highest when the Angle of the embedded defect was 90°,and the ratio of the tensile strength to the intact sample reached 90.11%.（3）On automatic laying corrugated defect on the tensile properties of laminated plates is to research the influence of the experiment the layer order of laminated plates with[（0°/90°）₂]as the foundation,will ripple shortcomings respectively set in 0°direction of fiber layer,0°and 90°direction of fiber layer and 90°direction of fiber layer in three different situations,and each case set 6 kinds of defects spacing variable respectively 0,1.6 mm,3.2 mm,6.35 mm,12.7 mm and 25.4 mm,and then to tensile experiment samples test and analysis of tensile experiment data.The experimental data showed that when the corrugated defect was set at 0°direction,the tensile strength of the sample increased first and then decreased as the gap between the two corrugated defects increased.When the gap between the two corrugated defects was 3.2mm,the tensile strength of the sample reached the maximum value.When the corrugated defect was set at the direction of 0°and 90°respectively,the tensile strength of the sample increased first and then decreased as the gap between the two corrugated defects increased.When the gap between the two corrugated defects was 3.2mm,the tensile strength of the sample also reached the maximum value.When the corrugated defect is set at 90°direction at the same time,the tensile strength of the sample increases with the increase of the gap between the two corrugated defects.