Ireneusz Wróbel

Diagnostics of machine parts by means of reverse engineering procedures

In this article, an application of a three-dimensional scanner for building a special diagnostic stand is described. An experimental method of detection of material defects is discussed. The considered defects are connected with cooperation of particular surfaces of machine parts. In the discussed experiments, particularly the dimensions of pitting holes can be evaluated. Availability of laboratory facilities required that the investigations were performed using geared wheels. The three-dimensional model which represents a degenerated surface, obtained based upon the diagnostic measurements, was compared with the pattern of an undamaged surface. The latter was generated by means of our pre-processor. The pre-processor enables generation of files which are compatible with the majority of the computer-aided design system formats. Therefore, the analyses were performed by means of commercial system inventor and computer-aided three-dimensional interactive application.

Nonlinear FEM models optimization on example of a stamping die

Modern software for computer-aided design, using the finite element method, more and more often contain modules for solving optimization tasks. The user may formulate and solve such problems as:  parametric optimization (geometry optimization), where the decision variables are the dimensions or cross-sectional parameters of the FEM model, and the objective function may be stress, nodal displacement or natural frequency;  topological optimization, where the shape of the designed part is sought, which ensures its best distribution in the space due to the criterion of maximum stiffness, minimal natural frequency, etc.;  sensitivity analysis, in which the impact of changing selected parameters of the FEM model on the indicated size (criterion) is examined to determine the relevant parameters and eliminate the non-essential ones due to the improvement of a given criterion. In the mentioned problems, the optimization task is solved:

Reverse Engineering of Stamping Die Punch – A Case Study

The paper presents a methodology developed by the author for reconstructing surfaces of shaping the punch which is an element of the stamping die. It describes the entire process of the punch reconstruction i.e. 3D scanning, modeling, FEM analysis and processing. This process was implemented by the stamping press cooperating with the authors. Conclusions have been formulated.

Stamping Die Modelling with Consideration to Drawpiece Springback Phenomenon

Drawpieces made of advanced high-strength steel (AHSS) usable for production of self-supporting car bodies are characterized by the presence of the springback phenomenon caused by the stress relaxation of the elastic part which is the result of stamping. Its compensation requires proper verification of die tools. The presented paper describes a methodology using CAE for die design. The methodology solves an optimization problem determining the verified shape of die tools upon taking into account the consistence of the drawpiece shape with the shape postulated in the project. The real drawpiece was used to judge the usefulness of the methodology in die design.

Evaluation of the feeder duct strength during short circuit

Streszczenie: Szynoprzewody, służące do przewodzenia dużych prądów, powinny zapewniać bezpieczną eksploatacją również podczas przewodzenia udarowego prądu zwarcia – kiedy działa na nie siła pola elektromagnetycznego o dużej wartości. W artykule przedstawiono dyskretny model MES do analizy naprężeń i deformacji segmentu szynoprzewodu w stanie zwarcia. Ponieważ analizowana konstrukcja okazała się bezpieczna, wyznaczono największy rozstaw podpór szynoprzewodu, przy którym jego eksploatacja jest jeszcze bezpieczna. Powiększenie rozstawu podpór szynoprzewodu pozwala na zwiększenie długości segmentu i obniżenie jego kosztów.

Numerical Effectiveness of the Simulation of an Automotive Body Part Stamping

The simulation of advanced high-strength steel sheet (AHSS) stamping processes by means of dedicated computer-aided engineering (CAE) software requires the use of appropriate material models, the use of complex FEM models, and the use of advanced methods for solving nonlinear problems of their analysis. In practice, the engineering design of automotive body parts often leads to the formulation of problems, the solution of which requires ample computer resources and is very time-consuming. The paper describes a methodology to simulate stamping on the example of a car body part, with special attention being paid to the numerical efficiency of the FEM model and methods of solving it. The simulations of stamping of a sample stamped part—the automotive body part—in DynaForm and AutoForm programs are compared, focusing on the numerical effectiveness and consistency of the simulation results with the reality.