Risultati finali
NAFEMS has published a survey on FE Analysis of contact and friction and a booklet on how to undertake contact and friction analysis. A contact benchmarks report on two-dimensional problems was published as the first step in establishing a set of FE Contact benchmarks. It was acknowledged that although the current published NAFEMS benchmarks were limited in scope, they were important as the first step in establishing contact benchmarks.
A small FENET Working Group on Contact has been assembled with the collaboration of the NAFEMS CSM Working Group. Following discussions on the development of new advanced benchmarks, it 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.
This report, presents outcomes from the Education and Dissemination Workshops held at Noordwijk and Palma on October 2003 and March 2004 respectively. The results from a round-robin exercise, completed as part of this activity, are also documented. These workshops and the round-robin, examined the procedures used in various industry sectors for the modelling and assessment of common fabrication details in plate/shell construction. The primary aim of this exercise was to examine "best practice" in modelling and assessing such detail (with general shell elements) and to disseminate this to the FENET membership and beyond. However, the round-robin was seem as an excellent opportunity to examine such practice and to observe resulting educational and quality assurance related issues.
It was anticipated that the unique forum provided by FENET would provide an excellent basis for these studies. As part of this work package, three procedural benchmarks were developed to reflect some of the modelling issues relevant to fabricated structures. These benchmarks and selected reference solutions, will provide a worthwhile educational resource. The benchmarks also formed the basis of the round robin exercise. While the benchmarks have many of the characteristics of traditional benchmarks, they differ in that they are designed to focus on some of the modelling issues that analysts are faced with and the various procedures adopted in the analysis and assessment process.
Section 1 of the report provides a brief overview of the various workshops involved in this study, as well as some background to the topic area. The specifications for the Procedural Benchmarks and pro-forma results forms are presented in section 2. These should provide a useful reference for any organisation intending to use them as part of, say, a staff development programme. Observations from the round robin are included in section 3 and these detail some surprising results. In the first two benchmarks about half of the respondents provided results, which suggested that they had made modelling errors. In the third example, only two out of ten respondents realised that this is a nonlinear geometric problem.
Whilst some contributions were no-doubt completed under time pressure, it can be argued that this is a reflection of the everyday industrial environment for many engineers. The resulting levels of human error and lack of results checking, for what some might regard as simple case studies, must be of wider interest and concern. The general spread of results arising from the different modelling and assessment strategies should also be of interest.
The outcomes certainly confirm the ongoing role that organisations such as NAFEMS have, in ensuring quality and promoting the education and development of analysts and engineers. Hopefully the educational and quality implications from the study will provide some impetus to general activity in this area. It is interesting to reflect on the fact that the same exercise and same general conclusions could probably have been made 30 years ago.
FENet was a Thematic Network, funded by the European Commission for four years from August 2001. The net work sought to coordinate activities within Europe aimed at improving both the quality of industrial applications of finite element technology and the level of confidence that can be placed in the computed results.
In excess of 110 organisations were members of FENet, representing the following industry sectors:
- Aerospace;
- Land transport;
- Bio-medical;
- Civil construction;
- Consumer Goods;
- Marine & Offshore;
- Power and Pressure Systems;
- Process and Manufacturing.
The activities of the network were focussed on three technology areas: Durability and Life Extension, Multi-Physics & new Technology and Product & System Optimisation. Running parallel to these technology areas were the general thematic activities of Education, Dissemination and the Identification of Strategic Research and Development needs.
A principal objective of FENet was to collate and structure existing information and to facilitate the efficient exchange of experience and knowledge within, and between, different industrial sectors within the European Community.
The industrial application of finite element technology has expanded dramatically. It has become a generic enabling technology across a broad spectrum of industrial sectors and across application areas within each sector. Given this widespread application its importance to industry is clearly profound. However, as this report highlights, the use of finite element technology within the various industrial sectors varies considerably.
This report contains the papers presented at the final meeting of the FENet project in May 2005. It is composed of individual reports from the coordinators responsible for:
- Each industry sector;
- Each technology area;
- Education and dissemination.
In addition, there is a paper from Dr. Nigel Knowles, which presents an overall summary of many of the findings of the FENet project.
This report introduces finite element volume methods for the modelling of welds and it depicts a brief history of the simulation of welds. A description of the heat flow processes and solid phase transformations is given in the theoretical background section. The procedure of thermal and mechanical finite element analyses is explained in the third section, titled Finite Element Weld Simulation, which also presents other examples of finite element analyses and describes the effects of solid phase transformations incorporated in the simulation of welds.
In the fourth section of the report, related research published in literature is discussed, proposing many modelling considerations which are relevant to weld simulation. This includes parametric studies and characterisation of residual stresses, the effect of material properties on residual stresses, three-dimensional geometric influences, an outline of the adaptive mesh technique and the shrinkage volume approach, and the combination of welding simulation with other heat transfer engineering processes.
Friction stir welding is described in the penultimate section of the report, which is followed by a description of the process of inertia friction welding. The finite element simulation of the two types of friction welding is discussed.
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