Session: 01-03 -01: Advanced Manufacturing and Process–Structure Relationships in Aerospace Structures

Paper Number: 196210

196210 - Rubber Forming and Rubber Bladder Hydroforming With Ls-Dyna 

Forming sheet metal using rubber is vital in industries such as aerospace, where low-volume production does not justify massive investments in multiple physical tool iterations. This process saves at least half the die cost in terms of material, casting, NC machining, and trial spotting. Simulation of rubber forming and rubber bladder hydroforming manufacturing processes is critical because they further reduce costs and shorten product design, development, and manufacturing cycle times. It replaces costly, time-consuming physical "trial-and-error" with virtual validation and iterations.
Properly engineered dies in a computer-aided environment can dramatically reduce both costs and development time. By using Finite Element (FE) simulations, engineers can predict how both the sheet metal and the rubber will behave before any physical tools are built. With FEA simulation, potential failure points—such as material thinning, wrinkling, and deformation around the gauging pins—can be identified and addressed for complex parts, such as aircraft wing ribs, in the early design phase, months before a physical die is built. Countermeasures can be developed to address these critical issues using computerized simulation iterations. Information such as forming force, pressure distribution, and springback can be evaluated, and tool geometry can be compensated based on the predicted springback to meet the design tolerance. 
In this presentation, we will use a rail to demonstrate both forming types, including springback, with discussion focusing on the following issues:
1.Rubber material model/element type.
2.Material model for sheet metal (specifically aluminum) and element type.
3.Contact types between various interfaces.
4.Mass scaling for explicit, and the potential for implicit analysis.
5.Springback compensation.
6.Model size and computational speed.
7.Methods to reduce the number of elements on the rubber block for faster computation.

Presenting Author: Li Zhang Synopsys, Inc.

Presenting Author Biography: Dr. Li Zhang has 17 years with Chrysler and DamilerChrysler in Stamping Die Manufacturing Engineering,
19 years with Livermore Software Technology Corporation, Ansys, and Synopsys in manufacturing software development and manufacturing process application engineering. He has a Ph.D. in mechanical engineering.