Crack Dynamics in Metallic Materials

Abstract

Le spese di stampa di questo volwne sono in parte coperte da contributi del Consiglio N azionale delle Ricerche. This volwne contains 286 illustrations.This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. ISBN 978-3-211-82226-5 ISBN 978-3-7091-2824-4 (eBook) DOI 10.1007/978-3-7091-2824 © 1990 by Springer-Verlag Wien Originally published by CISM, Udine in 1990. Springer-Verlag WienIn order to make this volwne available as economically and as rapidly as possible the authors' typescripts have been reproduced in their original forms. This method unfortunately has its typographical limitations but it is hoped that they in no way distract the reader. Dynamic (inertia and strain rate) effects influence crack growth processess if the applied loading rate is sufficiently high or if the crack tip moves with a speed that is a significant fraction of the wave velocities. In the paper basic results as well as solutions to boundary value problems incorporating dynamic effects are discussed. The integral expression for the energy flow to a moving crack tip is derived and related path-area integrals are discussed. It is shown that these quantities are non-trivial only if the energy density behaves as O(rlll). The ]-integral emerges as a special case of the general formulations. For linear dynamic problems a line integral defined in the Laplace transform space is introduced. The asymptotic field of a crack growing dynamically in a linear elastic material is derived and the stress-intensity factors are defined. K 1 -solutions are discussed for a number of problems involving both stationary cracks under dynamic loading as well as moving tips. Asymptotic solutions are given for both stationary and moving tips in different non-linear materials with either rate-independent or rate-dependent elasto-plastic behaviour. These solutions provide the basis for a discussion of dynamic crack growth criteria. Finally, some aspects on numerical modelling of dynamic crack problems are briefly discussed. PREFACE

Post-Fire Susceptibility to Brittle Fracture of Selected Steel Grades Used in Construction Industry—Assessment Based on the Instrumented Impact Test

“…The impact notch-toughness tests of samples prepared in advance have been conducted conforming to the recommendations of the EN ISO 14556 code [19] on an instrumented Charpy pendulum JB-W450E-L (Figure 5), having the potential energy of 450 J. The R8 (American type) pendulum hammer has been selected for the tests, as it is understood that in construction industry an impact by a flat surfaced object is more probable (with respect to the classical R2 pendulum hammer of European type) [27]. The hammer was equipped with a transducer used to measure the force hitting the specimen and the displacement of the force application point accompanying the load application sequence was measured with an encoder.…”

Post-Fire Susceptibility to Brittle Fracture of Selected Steel Grades Used in Construction Industry – Assessment Based on the Instrumented Impact Test

“…The impact notch-toughness tests of samples prepared in advance have been conducted conforming to the recommendations of the EN ISO 14556 code on an instrumented Charpy pendulum JB-W450E-L (Figure 5), having the potential energy of 450 J. The R8 (American type) pendulum hammer has been selected for the tests, as it is understood that in construction industry an impact by a flat surfaced object is more probable (with respect to the classical R2 pendulum hammer of European type) [27]. The hammer was equipped with a transducer used to measure the force hitting the specimen, and the displacement of the force application point accompanying the load application sequence was measured with an encoder.…”