Sławomir Polak

Quasi-static and dynamic deformation of double-hat thin-walled elements of vehicle controlled body crushing zones joined by clinching

A controlled body crushing zones are of considerable interest to automotive industry. The most popular technique of joining deformable zone components is spot welding. This paper presents a new technique of joining these elements using a metal forming process called clinching. Two methods of clinching: round press joining (RPJ) and square press joining (SPJ) are considered. Quasi – static and dynamic crushing tests of thin-walled specimens joined by clinching were carried out. The results show that clinch joining could be applied in controlled body crushing zones.

The use of thin-walled sections for energy absorbing components: a review

This paper presents the key aspects of the use of thin-walled sections for collision energy absorbing components. The process of deformation of thin-walled structures and the parameters expressing their energy absorption are described in detail. The research on improving the energy absorption of thin-walled sections, through the use of, e.g., tailored blanks, polyurethane foams and mechanical joining methods, conducted for many years in the Institute of Production Engineering and Automation at Wroclaw University of Technology is reported.

The Influence of the Punch Shape and the Cutting Method on the Limit Strain in the Hole Expansion Test

The article presents a comparison of the hole-flange factors for four steel sheets which have different strength parameters. Three types of punches were applied in the research: cylindrical, spherical and conical. The holes in the samples were made with the use of the following cutting technologies: laser cutting, electrodischarge method using wire and punching. The coefficient of the hole expansion shows that the shape of the used tools has a great impact on the final diameter of the hole. The greatest enlargement of the diameter was obtained for the conical punch, a smaller enlargement for the spherical one and the smallest enlargement for the cylindrical punch. The results of the hole expansion tests using the conical punch diverge from the general rule saying that the greater the plastic deformation of the sheet metal during tensile tests, the more you can enlarge the hole before cracking appears.