Hydroforming

About: Hydroforming is a research topic. Over the lifetime, 2796 publications have been published within this topic receiving 26293 citations. The topic is also known as: Bulge forming.

A new simulation-based metaheuristic approach in optimization of bilayer composite sheet hydroforming

Abstract: Simulated annealing which has been recently used in engineering applications is one of the most popular metaheuristic algorithms to solve optimization problems. In this work, an adaptive simulated annealing (SA) technique coupled with an adaptive finite element method is proposed and developed to optimize bilayer composite sheet hydroforming process. The aim of this combinatorial procedure is to obtain optimal forming pressure loading path to develop a new definition of SA algorithm parameters, to create an adaptive finite element (FE) code, to produce desired products with minimum thinning, and to avoid wrinkling and bursting failures. All of the effective SA parameters including Markov chain number, cooling function, initial temperature, and final temperature are redefined and developed to reduce excess iterations in FE simulations, hence saving the time and energy during the optimization process. The proposed optimization technique is employed to investigate the effect of layers sequence and thickness ratio on minimum cup thinning and optimal pressure load in hydroforming of aluminum/steel composite sheet. The experimental results demonstrated that the proposed adaptive method could be a reliable technique for optimization of processes with a large search space. It is also shown that it provides precise results in a shorter time by redefining the algorithm parameters.

Method and apparatus for manufacturing metal bent pipe having bulge

Abstract: PROBLEM TO BE SOLVED: To provide a method for manufacturing a metal bent pipe having a bulge capable of making manufacturing costs inexpensive. SOLUTION: The method for manufacturing the metal bent pipe having a bulge is characterized in that the method is a manufacturing method of a metal bent pipe 1 where the pipe is curved in the intermediate portion of the longitudinal direction and the bulge 1d is formed on the curved portion. A hydroforming die 10 having a restraining portion 13, composed of an upper and lower die 11, 12, to restrain pipe expansion in both end portions of a stock pipe P made of a metal and a cavity 14 to form the bulge portion 1d is prepared. When the die clamping force of both vertical dies 11, 12 of the hydroforming die 10 is performed, the stock pipe P is bent and a fluid pressure is introduced into the stock pipe P to form the bulge 1d under this condition. COPYRIGHT: (C)2003,JPO

Investigation of air bending of structured sheet metals by multistage FE simulation

Abstract: The improvement of the stiffness properties of the lightweight constructions using structured sheet metals is becoming more and more popular. These sheet metals have a three-dimensional geometry which causes better stiffness, heat conductivity and acoustic properties. However, this geometry brings besides many advantages several challenges for the following processing of these sheet metals. The main challenge is the different material behaviour depending on the bending position and structure location. In this work, the air bending of structured sheet metals was investigated. A numerical model was developed to predict the process safety and the bending line form. The model consists of two separate steps: hydroforming (manufacturing process of structured sheet metals) and air bending. Each simulation step was validated by series of experiments. The results show that the structured sheet metal has favourable and not favourable bending positions. At the structure location “positive” the bending quality is better than at the “negative”. Furthermore, the FE model allows the prediction of the strains in the bending zone in variable bending position and analysis of the process parameters of both forming steps.

Piercing method and piercing apparatus using hydroforming and hydroformed part and structure

Abstract: The present invention was made with the object of eliminating the short pipe member when attaching a bolting nut to a hydroformed part, preventing an increase in the difficulty of hydroforming for attaching the nut, extending the nut length so as to enable sufficient strength at the time of bolting, and enabling application even to thin wall hydroformed parts and comprises inserting a metal pipe into a split mold having a pierce punch able to be moved perpendicular to an axis of the inserted metal pipe or in a slanted direction, having a front part narrower than a center part, and having around the front part a nut having an inside diameter larger than an outside diameter of the front part and smaller than an outside diameter of the center part; hydroforming it; then making the pierce punch advance to pierce part of the hydroformed part and pushing the nut by a center part arranged behind the nut and embedding the nut in the metal pipe.