Finite element meshes can today be used to represent very complex structures because of high performance hardware and software. Although a very successful contributor to…
Finite element meshes can today be used to represent very complex structures because of high performance hardware and software. Although a very successful contributor to modern engineering analysis, such techniques are prone to certain classes of numerical analysis errors which have been long recognized and widely investigated. A more recently recognized source of error has, however, received the attention of analysts, being due to the shape distortion effects of popular types of element, such as isoparametric elements. A mesh scanning program, BERQUAL, part of the BERSAFE system, highlights such potential sources of error, but a more precise assessment is only possible from the final results since element performance depends on the stress gradients in each element. Hence additional error checking using certain stress error measures has been devised and implemented in the post‐processing program PLOTTER, part of the BERSAFE system, to enable rapid, interactive, screen diagnosis. The error measures and implementation details are described and illustrated with suitable examples of progressive shape distortion effects.
The nonlinear dynamic modelling of safety net systems is approached at different scales. For this purpose, the fundamental rope dynamic tests are the reference for two basic tools. One hand an analytical bidimensional model with explicit geometrical nonlinearity and bilinear material law is proposed for preliminary design. On the other hand, a nonlinear explicit finite element is defined for numerical modelling of net systems. Semi‐scale and full scale dynamic tests are performed to validate complete finite element models, suitable for global qualification of safety systems. The direct applications of these tools deal with explicit certification of safety systems for high‐speed sport, such as downhill competitions.
Follows a presentation at a symposium in 1993 where the authors presented an experimental investigation on a fluttering membrane for use in a wind‐tunnel. Analyses the…
Follows a presentation at a symposium in 1993 where the authors presented an experimental investigation on a fluttering membrane for use in a wind‐tunnel. Analyses the fluttering of an object by a theoretical method. Compares the experimental results with those of the theoretical and discusses their effectiveness. States that the present analysis is effective for approximate investigations.
Selection of suitable sewing needle is one of the most important parameters for ensuring an effective and fault‐free sewing process. This task requires good knowledge of…
Selection of suitable sewing needle is one of the most important parameters for ensuring an effective and fault‐free sewing process. This task requires good knowledge of basic characteristics of a sewing needle, i.e. needle type, point shape and needle fineness. Also good knowledge of sewing materials is required. The contribution presents an analysis of important parameters that influence the sewing needle selection in women’s underwear production. The importance of those parameters in ensuring the appropriate seam quality is described. The selection of a suitable sewing needle was carried out on the basis of analysis of influential sewing parameters with application of machine learning from examples.