Research On Lightweight Bearing Structure Design And CMT Additive Technology

Lightweight design is the main goal of structural design,while ensuring the strength and rigidity of the structure,reducing the quality and improving the performance.Benefiting from the development of wire and arc additive manufacture technology,it provides a variety of possibilities for the realization of complex structures,and it is increasingly important to obtain lightweight performance through structural design.In practice,wire and arc additive manufacture is not completely free to print,and is also constrained by process size and material characteristics.How to effectively combine the lightweight design with the additive technology,and at the same time to make use of the advantages of the two has become an important issue for the actualization of the lightweight structure.In this paper,the bottom plate bearing structure of special vehicles is taken as the research object,and the hollow core sandwich structure is used as a lightweight method.Use simulation method to determine the structure has the best load-bearing effect when the shape of the hollow core sandwich is regular hexagon.The size of the process size is determined by studying the size of the additive process.The specific size of the lightweight load-bearing structure under the design of the additive process is the core width.The high size is 20 mm and 38 mm,the best upper and lower panel thickness is 3.5mm and 5mm.The CMT molding process of the typical structure of the hollow core bearing model was studied.The effective molding thickness and molding accuracy of the inclined wall increased with the increase of the deflection amount through the process experiment.The deflection amount was 36%,and the limit forming angle was 39.6 °;The effective forming thickness of the suspended wall increases with the increase of the wire feed speed and the additive speed,the surface flatness decreases with the increase of the feed speed,the best parameters of the flatness are the additive speed 30 cm / min,the wire feed speed 5m / min;When the ratio is 30%,the flatness of the plane structure is the highest,and the standard deviation of the plane is 0.2.In view of the problems of high-strength steel additive structure microsegregation,uneven performance,and materials that cannot meet the design requirements,the WAAM high-strength steel was quenched and tempered at different temperatures.The study showed that after heat treatment,the structure was homogenized and the tempering temperature increased,The transverse and longitudinal tensile strength of the heat-treated parts are reduced,and the transverse and longitudinal elongation are increased.At the tempering temperature of 350℃,the longitudinal tensile strength is increased by 7%,the transverse tensile strength is increased by 12%,and the transverse elongation is increased by 8%,The longitudinal elongation increased by 7%.Finally,through the path planning,the printing of the hollow core bearing sample was completed,which verified the feasibility of the additive design of the design structure,and its forming accuracy basically met the design requirements.The study found that for the upper and lower parts of the sample,the use of the interlayer arc starting point rotation path is better for forming quality;for the overall lightweight bearing sample,adding in-plane arc starting point rotation on the basis of the inter layer arc starting point rotation Increase molding accuracy.