| Medium and hard commercial trucks usually have beam-structural frames which are either load-holding structural component or the train-driven component .Lengthwise beam is the mean structural component of this frame and its normal lifetime is usually more than twice heavy repairing period of the engine .How to make sure a lengthwise beams'lifetime and precision via an advanced stamping technology to meet the demand of high qualified commercial trucks is the key point in lengthwise beam stamping researching field .Whereas in the practical situation of the lengthwise beam manufacturing, because of a very big thickness,a huge difficulty of deformation and a huge deformational force, there are definitely some deformational defective .And the drawbacks mainly take place during bending, especially the bending crack and springback which make the rate of eligibility reduce sharply; also threaten the security of vehicle.This dissertation start with the cooperation of technical department of FAW Frame Workshop, aiming at trouble-shooting of the deformational defectives and controlling the quality of the lengthwise beam manufacturing via a high-tech FEM calculating method to analyze the practical manufacturing conditions and bending deformation .The final aim is to get a conclusion of how to make the manufacturing go better. Above this, there should be a proposal of further optimized method via a FEM calculation. In this dissertation, theoretically, the manufacturing conditions have been analyzed, as follows: (1) Metal cutting in the cutting machine (2) Punching technics holes (3) Bending (4) Punching holes on the bottom side (5) Punching holes on the lateral sideObviously the bending deformation is the key step of manufacturing. During practical manufacturing, main defective-- bending crack and springback take place. This dissertation theoretically analyzes the stress-strain condition,chemic ingredients,deformational properties and the main cause of the defectives etc. and...
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