Research on Hydraulic Push-Pull Bending Process of Ultra-Thin-Walled Tubes

Due to their high strength, high performance, and lightweight characteristics, bent tubes are widely used in many high-end industries, such as aviation, aerospace, shipbuilding, automobile, and petrochemical industries. Ultra-thin-walled (thickness-to-diameter ratio t/D < 0.01) bent tubes are more prone to wrinkling, fracture, and cross-section distortion than ordinary bent tubes, which are difficult to form integrally by traditional bending processes. In this paper, a new bending process with combined loading of hydraulic pressure, push, and pull was proposed to provide a new method for the bending of ultra-thin-walled tube. This process is characterized by the ability to optimize the combination of push, pull, and internal pressure according to the actual bending process in order to minimize the wrinkling of ultra-thin-walled tube during bending. Based on ABAQUS finite element (FE) software, the FE model of the hydraulic push-pull bending process for ultra-thin-walled tube was established. The influence of internal pressure, die clearance, and friction coefficient on the forming quality of bent tubes was discussed, and the optimum process parameters were obtained. Bent tubes with an initial thickness of 0.3 mm, diameter of 60 mm, and bending radius of 165 mm were manufactured in experiments. Through the comparative analysis of experiment and simulation, the accuracy of the FE simulation was verified.

THE DESIGN, ANALYSIS AND CRASHWORTHINESS OF AN ORIGAMI-INSPIRED STRUCTURE

Origami, the art of paper folding, is often associated with Japanese culture. Implementing- ing origami into products that make lives easier and that achieve desirable attributes is the main aim of the origami-adapted design process. A thin-walled tube such as a trapezoid origami crash box is one such energy absorption device derived from origami. The surface of this tube is pre-folded to develop an origami pattern that is delicately designed which gives rise to an interesting- ing structure on the surface of a square tube. Geometric, compliance, and comparative analysis are made and the two extreme designs, Trapezoidal and Diamond origami crash boxes are compared for their energy absorption capability.

THE DESIGN, ANALYSIS AND CRASHWORTHINESS OF AN ORIGAMI-INSPIRED STRUCTURE

Origami, the art of paper folding, is often associated with Japanese culture. Implementing- ing origami into products that make lives easier and that achieve desirable attributes is the main aim of the origami-adapted design process. A thin-walled tube such as a trapezoid origami crash box is one such energy absorption device derived from origami. The surface of this tube is pre-folded to develop an origami pattern that is delicately designed which gives rise to an interesting- ing structure on the surface of a square tube. Geometric, compliance, and comparative analysis are made and the two extreme designs, Trapezoidal and Diamond origami crash boxes are compared for their energy absorption capability.

A New Method of Manufacturing Thin-Walled Tube Made of AZ61 Magnesium Alloy Including Direct Extrusion And Corrugated Equal Channel Angular Extrusion

Due to demand of strong toughness of thin walled tube, and good secondary forming properties and high-precision dimension, New plastic forming method should be researched to achieve a complete filling, uniform deformation and microstructure evolution during forming process.To obtain the deformation mechanisms of a new composite extrusion for thin walled tube fabricated by tube corrugated equal channel angular extrusion has been researched which is shorten as “TC-ECAE” in this paper. Finite element DEFORMTM-3D software to investigate the plastic deformation behavior of magnesium billet during TC-ECAE process has been employed. Computed parameters including workpiece material characteristics and process conditions have been taken into consideration. The pridictions of strains distributions and damage distributions and effective stress distributions and flow velocities distributions and microstructures evolutions have been explored. The results proved that the TC-ECAE process is a forming method for magnesium alloy tube which is suitable for large scale industrial application. The TC-ECAE process would cause serve plastic deformation and improve the dynamic recrystallization of magnesium alloy during TC-ECAE process.