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Summary In this contribution, a three‐dimensional frictional contact formulation in the form of an interface solid finite element is discussed. The interface element incorporates normal as well as tangential contact conditions and aims at the modeling of phenomena occurring in engineering problems on the interface between different materials. The focus of this work lies on the description of the tangential interaction of bodies on their contact interface. Instead of the widely used Coulomb friction law, a simple elastoplastic material law is applied in order to model the interaction mechanism on the tangent plane. Appropriate local coordinate systems are introduced on the surface and point of contact, and all contact operations are performed in these coordinate systems by adopting a fully covariant description. In this way, we derive a symmetric element stiffness matrix not only for the case of sticking but also for sliding. Exploiting the advantages of the covariant description, we show that the fact that the derived stiffness matrix discretely consists of constitutive and geometrical parts enables us to introduce rather straightforwardly new appropriate interface laws describing the tangential interaction of the contacting bodies. The presented numerical results show very good correlation of the developed approach with ‘pull‐out’ experiments. Copyright © 2016 John Wiley & Sons, Ltd.

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Der vorliegende Beitrag beschäftigt sich mit hochdynamischen Einwirkungen auf das Material Beton und auf Stahlbetonkonstruktionen. Zunächst werden die Grundlagen zu den hochdynamischen Einwirkungen Explosion und Impakt kurz beschrieben. Materialien verhalten sich unter diesen Einwirkungen anders als unter statischen Einwirkungen, weshalb auf die Materialmodellierung eingegangen wird. Verfahren der Strukturdynamik können bei Einwirkungen, die lediglich über Millisekunden wirken, gar nicht oder nur in Ausnahmefällen eingesetzt werden. Die sogenannten Hydrocodes sind hier besser geeignet. Anschließend wird gezeigt, wie Stahlbetonkonstruktionen im baulichen Schutz eingesetzt und dimensioniert werden. Um die Anforderungen an die Schutzelemente zu erfüllen, ist die konstruktive Durchbildung von besonderer Bedeutung. Hierfür werden Beispiele aufgeführt. Concrete and Reinforced Concrete Structures Subjected to Explosion and Impact The present paper deals with high dynamic loads acting on concrete material and on reinforced concrete structures. First the explosion and impact events are described briefly. The behavior of materials subjected to high speed loading is different from the behavior under static loads. Therefore concrete material modeling will be shown. Methods of structural dynamics can usually not be applied because high dynamic loads only act over a time period of milliseconds. Therefore a class of hydrocodes will be used. Further the design of reinforced concrete structures which are subjected to explosion and impact is presented. In order to meet the design requirements the corresponding structural detailing has to be considered. Examples will be presented.

This contribution proposes a tribological model within a three‐dimensional contact formulation considering structural anisotropy of the contact interface. A simple elastoplastic constitutive law is adopted for the description of the behavior on the anisotropic contact interface. Starting with the establishment of the thermodynamic framework of the contact problem, the dissipative, irreversible process is described. By applying the principle of maximum dissipation, the evolution equations and the expressions of the tangential contact forces for the cases of sticking and sliding are obtained and, subsequently, formulated in algorithmic form, in order to enable their implementation into finite element codes. The anisotropic behavior is incorporated through the definition of a tensor of anisotropy. The form of this tensor is defined in a general curvilinear coordinate system. The cases of both constant and nonconstant anisotropic tensor are studied. The analytical solution of a numerically computed problem, serves the validation of the proposed model.