This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic ...This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic resin (GF/PF). The CF/Epoxy was placed in the mold cavity prior to injecting GF/PF onto the inserted injection molded CF/Epoxy specimens. The role of adhesion between the inserted part and injected resin on the mechanical properties was evaluated by 3 point bending and impact tests. In addition, the effect of prepreg orientation on the mechanical properties of the prepreg inserted-injection molding system was investigated. It was found that the prepreg with unidirectional orientation significantly improved flexural and impact strength of the inserted injection molding composites, providing better support and resistance to bending and impact loading. The main failure modes of the specimens were structural and adhesive failure.展开更多
With the growing needs of prepreg tapes for the automated fiber placement(AFP),the deviation-rectifying of prepreg in slitting process was investigated on a self-developed 16-tow prepreg slitting and winding machine.T...With the growing needs of prepreg tapes for the automated fiber placement(AFP),the deviation-rectifying of prepreg in slitting process was investigated on a self-developed 16-tow prepreg slitting and winding machine.The process of slitting and rewinding of prepreg tape was introduced,and the reason of prepreg tape deviation in slitting process was analyzed.In order to ensure the quality of the narrow prepreg slits,the application of the fuzzy PID algorithm in a closed-loop control system was discussed.A fuzzy PID algorithm was designed by combining fuzzy rules and PID controller.By applying it to precise deviation-rectifying control strategy,the automatic control of rectification could be achieved with accuracy of 0.1 mm,which satisfies the requirement of the prepreg tape both in slitting quality and layup quality for AFP.展开更多
Effects of layer quantities and stacking sequences on L-shape composite manufacturing qualities in using OOA(out-of-autoclave)prepregs were studied.The mechanisms of air evacuated in 5 kinds of lay-ups were revealed b...Effects of layer quantities and stacking sequences on L-shape composite manufacturing qualities in using OOA(out-of-autoclave)prepregs were studied.The mechanisms of air evacuated in 5 kinds of lay-ups were revealed by image analysis of cut surfaces and thickness measurements.Results show that air in OOA prepregs is evacuated in two ways.Most of the air is forced out of layers directly by vacuum before air accesses in prepregs closed.Very little entrapped air moves perpendicularly to outer layers under hydrostatic resin pressure.When a laminate contains less than 16 layers,voids can hardly be found in layers.When a laminate contains more than 16 layers,voids cannot be expelled completely during the window of vertical movement.As for stacking sequences,the synergetic effect of slip function and nest function determines the thickness and voids content of laminates.Results show that the average of single layer thickness of unidirectional layers is the lowest,and the average of single layer thickness of quasi-isotropic layers is the highest.The voids content of quasi isotropic is the highest,which is consistent with the theoretical analysis.展开更多
文摘This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic resin (GF/PF). The CF/Epoxy was placed in the mold cavity prior to injecting GF/PF onto the inserted injection molded CF/Epoxy specimens. The role of adhesion between the inserted part and injected resin on the mechanical properties was evaluated by 3 point bending and impact tests. In addition, the effect of prepreg orientation on the mechanical properties of the prepreg inserted-injection molding system was investigated. It was found that the prepreg with unidirectional orientation significantly improved flexural and impact strength of the inserted injection molding composites, providing better support and resistance to bending and impact loading. The main failure modes of the specimens were structural and adhesive failure.
基金financially supported by the National Basic Research Program of China(973Program)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Fundamental Research Funds for the Central Universities ( No. 3082615NS2015056)
文摘With the growing needs of prepreg tapes for the automated fiber placement(AFP),the deviation-rectifying of prepreg in slitting process was investigated on a self-developed 16-tow prepreg slitting and winding machine.The process of slitting and rewinding of prepreg tape was introduced,and the reason of prepreg tape deviation in slitting process was analyzed.In order to ensure the quality of the narrow prepreg slits,the application of the fuzzy PID algorithm in a closed-loop control system was discussed.A fuzzy PID algorithm was designed by combining fuzzy rules and PID controller.By applying it to precise deviation-rectifying control strategy,the automatic control of rectification could be achieved with accuracy of 0.1 mm,which satisfies the requirement of the prepreg tape both in slitting quality and layup quality for AFP.
文摘Effects of layer quantities and stacking sequences on L-shape composite manufacturing qualities in using OOA(out-of-autoclave)prepregs were studied.The mechanisms of air evacuated in 5 kinds of lay-ups were revealed by image analysis of cut surfaces and thickness measurements.Results show that air in OOA prepregs is evacuated in two ways.Most of the air is forced out of layers directly by vacuum before air accesses in prepregs closed.Very little entrapped air moves perpendicularly to outer layers under hydrostatic resin pressure.When a laminate contains less than 16 layers,voids can hardly be found in layers.When a laminate contains more than 16 layers,voids cannot be expelled completely during the window of vertical movement.As for stacking sequences,the synergetic effect of slip function and nest function determines the thickness and voids content of laminates.Results show that the average of single layer thickness of unidirectional layers is the lowest,and the average of single layer thickness of quasi-isotropic layers is the highest.The voids content of quasi isotropic is the highest,which is consistent with the theoretical analysis.
