Advanced Finite Element Contact Benchmarks II

A summary report of the FENet Durability and Life Extension (DLE) workshop in Majorca,Spain, 25th March 2004.

By Prof. Adib Becker, University of Nottingham, UK

Introduction

This workshop was the second FENET-DLE workshop on contact benchmarks, and is a followup to the contact workshop held in Copenhagen (27-28 February 2002). The first contact workshop addressed the difficulties experienced by FE users in modelling contact problems, current limitations of commercial FE software, desirable contact features that are not currently being offered by FE software, and the need for further research in the application of FE methods to contact problems.

NAFEMS has published a contact benchmarks report as the first step in establishing a set of FE contact benchmarks. It was acknowledged in the first FENET contact workshop that there is a need for developing more complex contact benchmarks.

A small “FENET Working Group on Contact” has been assembled with the collaboration of the NAFEMS Non-linear Working Group. Discussions on the development of new advanced contact benchmarks have been initiated.

Workshop Objectives

The objectives of the FENET contact workshop were:

• To discuss the requirements for advanced contact benchmarks
• To agree on a list of new (advanced) contact benchmarks
• To issue a request to FE software vendors and FE users to run the new contact benchmarks and report the results.

Analysis of Workshop

The workshop was chaired by Professor Adib Becker (University of Nottingham, UK), and attended by 14 delegates.

The chairman presented the following:

• An overview of the previous FE workshop on Contact benchmarks held in Copenhagen in February 2002
• A summary of the current published NAFEMS contact benchmarks
• A review of the good features and limitations of the published benchmarks
• A review of a number of suggestions for advanced contact benchmarks sent by FENET members and other FE analysts.

Discussions were held to evaluate the merits and disadvantages of each of the candidate contact benchmarks. Finally, was agreed to concentrate on only 5 contact benchmarks, as follows:

• 2D Contact of cylindrical roller
• 3D Punch (Rounded edges)
• 3D Sheet metal forming
• 3D Loaded pin
• 3D Steel roller on rubber

The selected contact benchmarks exhibit the following features:

• 3D contact
• Frictional stick-slip in contact area
• 2D/3D Linear vs. quadratic elements
• 3D 27 node brick elements
• Shell contact
• Large strain contact
• Metal forming
• Mesh dependency
• Compression of rubber
• Rolling contact

It was recognized that the dimensions and the material properties will play an important role in highlighting the relevant features of the contact benchmarks.

Therefore, further FE analyses will be performed to establish the geometric parameters, material constants, values of the applied loads and the coefficient of friction.

Future Work

The following is an outline of the agreed work plan for the establishment of a new set of advanced contact benchmarks:

Step 1 (Initiate discussion) - completed in February 2003 Assemble a small “FENET Working Group on Contact” of interested parties. Collaborate with the NAFEMS Non-linear Working Group. Initiate discussions on the development of new advanced contact benchmarks.

Step 2 (Agree benchmarks) - to be completed in June 2004 Agree on a list of new contact benchmarks. Issue a request to FE software vendors and FE users and to run the new contact benchmarks.

Step 3 (Launch final workshop) - to be completed in March 2005 Launch a further FENET DLE workshop on “Advanced Contact Benchmarks” to report the outcome.

Step 4 (Issue FENET Report) - to be completed in July 2005 Issue a formal report on Advanced Contact Benchmarks. It is expected that a formal report on advanced contact benchmarks will be published by NAFEMS in due course.