On The New Process Of Roll Forming Of Grid Rib Reinforced Plates

The rib stiffened plates have significant advantages in achieving product weight reduction,structural strength and specific stiffness,and are widely used.However,such components are difficult to produce using conventional methods,and there is an urgent need to develop new processing technologies that meet the requirements.This paper summarizes the production technology of existing ribbed members and analyzes the advantages and disadvantages of various processes.Aiming at the problems of large load and difficult control of traditional ribbed plastic forming method,a local and continuous plastic deformation of slab is proposed based on the concept of “rotary forming”,which results in large thickness difference of ribbed plates.A new method of "labor-saving forming" of complex shell and shell parts characterized by roll forming.The new method combines volume forming,sheet forming,and traditional processes such as roll forging and rolling,and adopts a forming principle different from that of reciprocating pressing of a mold to obtain various forms of shell-and-shell members with different thickness characteristics;The method has the advantages of high production efficiency and high material utilization rate,and effectively avoids the problems of large load and low mold life based on the reciprocating mold movement forming method,and has strong expandability,wide adaptability and wide application prospect.The paper analyzes the geometric mapping relationship between the shape of the groove of the roll mold and the profile of the ribs by use the typical grid ribs with transverse and longitudinal ribs.The numerical simulation is used to analyze the roll forming process of the grid ribs.The influence of main process parameters on the shape and forming load of the workpiece was discussed.Using the response surface method,the optimal combination of process parameters was obtained.Finally,the roll forming of the grid ribs was experimentally verified.The main conclusions are as follows:(1)Physical experiments and numerical simulations show that the rolling process can realize the formation of complex shapes of three-dimensional variable-section ribbed plates under lower load.Compared with the process of group welding and partial loading,it has significant advantages in terms of part quality,production efficiency and material utilization.(2)When the grid ribs are rolled,the deformation behavior of the transverse and longitudinal ribs is different due to the difference in stress state.Among them,the deformation of the longitudinal rib is similar to the extrusion forming,and its contour is more consistent with the shape of the mold groove.The relative relationship between the transverse ribs and the roll grooves is similar to an meshing motion.When the plastic flow is not used,the conjugate equation can be used to analyze the geometric relationship between the transverse rib profile and the groove.Overall,the filling capacity of the transverse ribs is better than that of the longitudinal ribs.(3)Studies have shown that the friction factor m and the roll diameter d have a significant effect on the size and load of the ribbed roll forming,while the roll speed n has a small effect.Aiming at the defects such as filling dissatisfaction and high horizontal and vertical rib height in forming,the m,d and groove outer fillet radius r are used as the optimization factors,and the optimized process parameters with satisfactory filling effect are obtained by the response surface method.(4)It has been found that the contour of the rear wall of the transverse rib is easy to form,and the contour of the front wall is missing at the end of the contour due to the back slip.Increasing the front and rear wall angles of the roller model groove,the transverse rib contour is closer to the theoretical calculation,and the forming effect is better.In addition,increased friction and proper interference can improve the filling effect of the transverse ribs.