Research On Induction Welding Technology Of Carbon Fiber Reinforced Polyphenylene Sulfide Composite

Thermoplastic composite material plays an important role in the lightweight,high performance and environmental protection of civil aviation vehicles.It is considered to be a new type of advanced aviation materials with a very promising future.The efficient and reliable connection of its structure is the important guarantee for its further extensive application.Aiming at the carbon fiber reinforced polyphenylene sulfide composite laminate,the influence of induction welding process parameters on the properties of the welded joint is discussed,obtains the best welding process parameters,determines the welding quality control window,and systematically studies the performance evolution of the welded samples after different heat and humidity treatment.First of all,the optimization calculation and analysis of the induction welding process parameters of CF/PPS laminated plate are carried out by using DOE experimental design.It is concluded that the welded joint has the best shear performance when the welding power is 2.0kw,the welding pressure is 1.5MPa and the welding time is 3.0min.In this case,the shear strength of the single-lap welded joint is about 13.25 MPa.In addition,all of the shear strength of the welded joints show a trend of increasing first and then decreasing with the increasing of the welding process parameters.Under the optimal welding process parameters,the structure of the welded joints is closely combined and shows high shear strength,while the structure is poorly combined with low shear strength when the welding process parameters are too low or too high.Then,the failure fracture of induction welded joint of CF/PPS laminate is analyzed.The results show that the stainless steel mesh at the fracture of high shear strength welded joint is torn,the interface fiber of welded laminate is pulled out and fractured,and the PPS resin has obvious plastic deformation,the main failure mode is interlayer failure.While the main failure mode in low shear strength welded joint is interface failure.At the same time,combining to the results of variance analysis,the interaction of welding power/welding time has a significant impact on the shear performance of the welded joint,the window of the welding quality control is designed and determined.It can ensure that the shear strength of the joint can reach about 73% ~ 88% of the interlaminar shear strength of the base metal of the laminated plate by selecting the process conditions in the welding window area I.At last,the influence of wet and hot environment on the properties of CF/PPS laminate induced welding joint is studied from the aspects of chemical structure,shear property and failure mechanism.The results show that PPS resin has no chemical change before and after moisture absorption.At room temperature,with the increase of moisture absorption time,the wet stress at the interface of stainless steel mesh/resin matrix/carbon fiber increases continuously,which weakens the interface knot of welding joint.In addition,the shear strength of the welded joint decreased by 15%,18%,23%,32% and 38% respectively compared with that of the dry welded joint.At 120 ?,the shear strength of the welded joint decreased by 12%,15%,22%,37% and 44% respectively at each moisture absorption time.Under the position of high temperature and high humidity,the interface debonding is the main failure mode of the welded joint,which leads to a significant decrease in the shear strength of the joint,because there are more large of the thermal stress and wet stress on the interface of stainless steel mesh/resin matrix/carbon fiber,and it aggravates the damage to the interface bonding property.