Vereinheitlichung von Proben für Schwingversuche

FKM 1996 Issue No. 217 Project No. 198
Abstract:

The short project "Standardization of specimens for vibration tests" was carried out as a questionnaire campaign. The questionnaire was designed to obtain comprehensive information on the specimen forms currently in use. Particular importance was attached to the question of existing experience with the respective specimen forms. In most cases, the data obtained is reproduced in the report without comment. In some cases, information on the shape number Kt and its determination was missing. However, shape numbers differ considerably depending on the determination method. Overall, the question about the experience gained with the samples was only answered unsatisfactorily. On the one hand, this may be due to the fact that certain necessities are taken for granted when carrying out vibration tests and, on the other hand, an understandable reluctance to answer this question when unfavorable experiences are available. The questionnaires received dealt exclusively with the specimen forms material specimen (smooth round bar, smooth flat bar, incl. LCF specimens) and notched bar as a component-like specimen. The majority of all questionnaires provided data on LCF specimens. For material tests on smooth specimens in stress or strain-controlled tests, the specimen shape developed by IABG with a radius sequence to simulate the transition from the clamping end to the test cross-section, in which the test length itself is formed by a large radius, was recommended. With this specimen shape, a shape number Kt = 1.0 is achieved. Breaks in the transition area were almost always avoided. Free-form transitions, which can be derived using the GAG method (Computer Aided Optimization) in conjunction with FE analyses, lead to the same results. However, as sample quality and production costs are generally in competition, the choice of sample remains a case-by-case decision. The existing testing machines and fixtures, the costs of specimen production depending on the number of specimens and the necessary measurement technology are some of the determining factors. This report therefore makes recommendations and outlines strategies that are based on existing experience and are intended to standardize specimens in the field of fatigue strength. However, this can only succeed on the basis of the broadest possible acceptance by the companies and institutes involved.

Scope of report:
40 text pages incl. images and tables, 101 sample forms

Start of work:
01. 01. 1995
End of work:
31.12.1995

Funding body:
FKM own funds

Research center:
Institute for Mechanical Plant Engineering and Structural Durability (lfB) Clausthal University of Technology (TUC)

Head:
Prof. Dr.-lng. H. Zenner Author: Dr.-lng. H. Buschermöhle (lfB)

Chairman of the working group:
Dr.-lng. C. Gerdes, ABB Kraftwerke AG, Baden Dipl.-lng. M. Lüdeke, Audi AG, Ingolstadt
Chairman of the Advisory Board:
Prof. Dr.-lng. H. Kipphan, Heidelberger Druckmaschinen, Heidelberg