Altair > Case Studies > Minimising Mass and Increasing Durability of a Vehicle Suspension System Using HyperStudy & OptiStruct

Minimising Mass and Increasing Durability of a Vehicle Suspension System Using HyperStudy & OptiStruct

Technology Category

Robots - Autonomous Guided Vehicles (AGV)
Sensors - Torque Sensors

Applicable Industries

Automotive
Equipment & Machinery

Applicable Functions

Procurement
Product Research & Development

Use Cases

Root Cause Analysis & Diagnosis
Vehicle Performance Monitoring

Services

System Integration

About The Customer

Gestamp is a global chassis component supplier for customers such as Ford, VW, BMW and Honda. Its technical centres which are based in the UK, Spain and Germany support an expanding global business with manufacturing sites throughout the world in developing low cost, high volume chassis products. Component mass and cost (strongly linked to mass) are drivers for every customer and Gestamp have been using an optimisation driven design process, based on Altair products, since 2005. Gestamp has recognised the potential for mass reduction through optimisation of a “U” section design.

The Challenge

Gestamp, a global chassis component supplier, was faced with the challenge of reducing the mass and increasing the durability of a rear twist beam (RTB) suspension system. The RTB design is a complex task that requires careful consideration of elastokinematic performance in addition to meeting stiffness and durability targets. The design of experiments (DOE) and optimisation methods were being used to explore the available design space and minimise the mass of a low cost RTB design. The durability requirement was identified as one of the main mass drivers for this type of RTB design. The design of a “U Section” RTB typically requires consideration of several interlinked targets, including Roll Stiffness and Roll Steer, which are strongly influenced by the shape, position and gauge of the torsion element.

The Solution

To address the challenge, Gestamp selected Altair to develop a set of custom tools, referred to as “The RTB Toolbox,” which can be used to generate an initial RTB concept that meets Kinematics and Compliance (K&C) requirements such as Roll Stiffness/Steer, thereby eliminating an initial “trial and error” design loop. The software used the functionality available within high-performance preprocessor HyperMesh to set up shape design variables for each component in the RTB assembly. HyperStudy was used to control DOE studies, which provided a detailed understanding of the sensitivity of each target to input parameters. This was followed by a final optimisation step from which the concept surfaces were generated. The next stage of the design process was to create a CAD model from the optimised Toolbox output. This model served as a baseline for work to meet durability and strength criteria.

Operational Impact

The development of the RTB Toolbox resulted in a reduction in design lead time for the initial concept which was carried through the project. An additional benefit of the Toolbox design approach was the use of DOE studies. These studies have proven to be valuable as a means of quickly gaining an understanding of the sensitivity of various K&C targets to input parameters, including the shape and position of individual parts within the assembly, along with their gauges. The optimisation capability offered by OptiStruct was used extensively in order to tune the Toolbox Output design in order to meet durability targets, whilst ensuring that K&C performance is maintained. Local shape optimisation of the torsion element trim edge was also used to successfully generate design variants with different levels of Roll Stiffness.

Quantitative Benefit