The main aim of the Tech-Spring project is to develop a toolkit to enable European Spring Manufacturers to help their customers design novel lightweight springs. The toolkit will be comprehensive in supplying advice about the design of compression, extension, torsion springs made from wire and also springs made from strip. It will be integrated with an existing computer aided design package providing accurate quantification of maximum stresses to utilise without compromising performance or reliability.
The Tech-Spring project has just completed the second of three years. At the end of April 2009 the following case studies / reports have been completed:-
Compression spring end coil failures.
Springs operating in the extension and compression mode.
Sub-surface fatigue failures without inclusions.
Factors affecting end hook failures in extension springs.
Effect of prestressing on compression spring fatigue performance.
Stress profile in compression springs made from wire larger than 6mm.(two reports)
Effect of speed of production on spring dimensions and load.
Effect of speed of testing on fatigue performance.
Effect of stress relief time on fatigue performance. (two reports)
Factors affecting the fatigue performance of torsion springs.(two reports)
Effect of coiling method on spring properties.
i) Torsion springs
ii) Compression springs
iii) Hot versus cold coilingStress analysis in springs made from strip.
Appearance due to shot peening.(two reports)
High Tensile Si Cr wire
Use of Strain Gauges to measure Dynamic Stress in Springs
Non Axial Resonances in Compression Springs
Finite Element Analysis of Spring Supplied by Turton Springs Ltd
Finite Element Analysis and Testing of Flat Strip Spring Clip
Low Cost Stress Analysis Tools Report
High Cost Stress Analysis Tools Report
Standards Activity Report
Software Features Report
Each of the case studies has yielded results and training opportunities during the second year of the Tech-Spring project, which should be exploited during year 3.
The first version of the CAD toolkit was issued to the partners at the mid term meeting. A further version two was issued to partners in August 2008 for evaluation. A third version of the Toolkit is due to be issued to Partners etc during May 2009 for evaluation.
The toolkit and its features will be presented in training programs given first to DSA and ANCCEM and then more widely in Europe in year 3.
Another aspect of the Tech-Spring project is the evaluation of advanced stress analysis methods, which includes:
i) Finite Element Analysis and MKS to calculate stresses in springs too difficult to calculate by other means.
ii) Use of a high speed camera to capture the true deflection of springs made and operated at high speed.
iii) X-ray residual stress analysis methods to quantify residual stress after heat treatment, shot peening and prestressing.
iv) Strain gauging to correlate with FEA and CAD outputs.
v) Non-axial force testing to identify how to minimise non-axial forces and to evaluate whether these undesirable forces affect fatigue life.
The toolkit will identify the circumstances in which these analysis methods would be a cost effective investment for spring manufacturers.
The team actively engaged on Tech-Spring comprises:
Two spring trade associations - DSA and ANCCEM, from The Netherlands and Italy.
Six SME companies involved in the spring supply chain or supply of stress analysis methods, these are:
Metalpol, Poland, spring manufacturer and FEA
Mollificio Mevis, Italy, cold formed spring manufacturer
Turton Springs, UK, hot formed spring manufacturer
Joh Pengg, Austria, supplier of oil tempered and drawn carbon steel spring wire
Lake Image Systems, UK, high speed cameras
Peen Services, Italy, X-ray residual stress analysis
and two research providers IST and Innotech from UK and Germany.
Progress has been behind the original plan, but the Consortium are confident that the overall work plan can be delivered within the 39 month time frame and on the original budget.
For more information contact the project coordinator, Mark Hayes, m.hayes@ist.org.uk.