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Michael May

Bio: Michael May is an academic researcher from Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut. The author has contributed to research in topics: Fracture toughness & Delamination. The author has an hindex of 17, co-authored 63 publications receiving 962 citations. Previous affiliations of Michael May include University of Bristol & Fraunhofer Society.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a detailed experimental characterization of quasi-static anisotropic directional strength properties as well as the shock behavior of ultra-high molecular weight polyethylene (UHMWPE) for the development of an advanced material model for this class of materials is presented.

106 citations

Journal ArticleDOI
Michael May1
TL;DR: In this paper, the authors compared different approaches to measure the mode I fracture toughness of composites under high rates of loading and provided recommendations for measuring the fracture toughness under high-rate loading.
Abstract: Composite materials are often subjected to mechanical impact causing delamination. For quasi-static loading, measuring the mode I fracture toughness has been standardized. However, for high-rate loading, additional challenges arise. Consequently, no standard test has yet been defined for measuring the mode I fracture toughness under high rates of loading. This article therefore reviews candidate tests for measuring the high-rate mode I fracture toughness. Strength and weaknesses of different specimen designs and test setups are shown. Different approaches to measuring crack growth and loads are presented. The different approaches are compared and recommendations are provided for measuring the mode I fracture toughness of composites under high rates of loading.

96 citations

Journal ArticleDOI
TL;DR: In this article, a model for the simulation of damage initiation and subsequent propagation under cyclic loading is proposed, which combines phenomenological SN-curves for damage initiation with a fracture and damage mechanics approach for crack propagation.
Abstract: A model for the simulation of damage initiation and subsequent propagation under cyclic loading is proposed. The basis for the formulation is a cohesive law that combines phenomenological SN-curves for damage initiation with a fracture and damage mechanics approach for crack propagation. The evolution of the damage variable is expressed as a function of fatigue cycles. The model is independently calibrated for mode I and mode II loading using SN-curves and Paris-law coefficients obtained from simple coupon tests. The model was applied to three initiation-driven cases: Bending of 90° laminates, the Short Beam Shear test and the Double Notched Shear test. The predictions for the first two cases showed an excellent correlation with experimental data. Some modifications to the model were required when applying it to the Double Notched Shear test.

88 citations

Journal ArticleDOI
TL;DR: In this article, the authors developed a fully rate-dependent constitutive law for cohesive interface elements considering both, the strain rate dependency of the initiation stress and the strain ratio dependency of fracture toughness.

79 citations

Journal ArticleDOI
TL;DR: In this article, the similarity between Peridynamics and Smooth-Particle Hydrodynamics is studied, and it is shown that the discretized equations of both methods coincide if nodal integration is used.

79 citations


Cited by
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Journal Article
TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

13,333 citations

01 Jan 1985

626 citations

Journal ArticleDOI
TL;DR: In this paper, the authors assess the recent trends in the numerical meshless method smoothed particle hydrodynamics, with particular focus on its potential use in modelling free-surface flows.
Abstract: This paper assesses some recent trends in the novel numerical meshless method smoothed particle hydrodynamics, with particular focus on its potential use in modelling free-surface flows. Due to its Lagrangian nature, smoothed particle hydrodynamics (SPH) appears to be effective in solving diverse fluid-dynamic problems with highly nonlinear deformation such as wave breaking and impact, multi-phase mixing processes, jet impact, sloshing, flooding and tsunami inundation, and fluid–structure interactions. The paper considers the key areas of rapid progress and development, including the numerical formulations, SPH operators, remedies to problems within the classical formulations, novel methodologies to improve the stability and robustness of the method, boundary conditions, multi-fluid approaches, particle adaptivity, and hardware acceleration. The key ongoing challenges in SPH that must be addressed by academic research and industrial users are identified and discussed. Finally, a roadmap is propose...

326 citations

Book ChapterDOI
01 Jan 2020
TL;DR: This chapter provides an extensive overview of the literature on the so-called phase-field fracture/damage models (PFMs), particularly, for quasi-static and dynamic fracture of brittle and quasi-brittle materials, from the points of view of a computational mechanician.
Abstract: Fracture is one of the most commonly encountered failure modes of engineering materials and structures. Prevention of cracking-induced failure is, therefore, a major concern in structural designs. Computational modeling of fracture constitutes an indispensable tool not only to predict the failure of cracking structures but also to shed insights into understanding the fracture processes of many materials such as concrete, rock, ceramic, metals, and biological soft tissues. This chapter provides an extensive overview of the literature on the so-called phase-field fracture/damage models (PFMs), particularly, for quasi-static and dynamic fracture of brittle and quasi-brittle materials, from the points of view of a computational mechanician. PFMs are the regularized versions of the variational approach to fracture which generalizes Griffith's theory for brittle fracture. They can handle topologically complex fractures such as initiation, intersecting, and branching cracks in both two and three dimensions with a quite straightforward implementation. One of our aims is to justify the gaining popularity of PFMs. To this end, both theoretical and computational aspects are discussed and extensive benchmark problems (for quasi-static and dynamic brittle/cohesive fracture) that are successfully and unsuccessfully solved with PFMs are presented. Unresolved issues for further investigations are also documented.

290 citations

Journal ArticleDOI
TL;DR: In this paper, an overview of the development of methods for the prediction of fatigue driven delamination growth over the past 40 years is given, and four categories of methods are identified: stress/strain-based models, fracture mechanics based models, cohesive zone models, and models using the extended finite element method.

225 citations