Nonlinear contact problems—A finite element approach implemented in ADINA

Abstract

In the analysis of structures or materials which consist of two or more components, special attention must be paid to their interaction. Whereas the assumption of complete compatibility between adjacent elements usually is sufficient in a global analysis, a more detailed calculation requires the realistic modeling of the contact interface. For this purpose an isoparametric contact element has been developed which is compatible to the two- and three-dimensional elements available in ADINA. The element can be used with a linear, quadratic, or cubic interpolation function. According to the isoparametric concept, curved element boundaries can be modeled respectively. At first, the element has been developed for the investigation of bond between concrete and reinforcement. Various bond stress-slip relations have been programmed including effects which significantly influence the bond behaviour, for example transversal pressure, although the application of the element is not restricted on bond problems. Due to the modular structure of ADINA, which has been maintained in the programming of the contact element, additional stress-slip relations can be incorporated on the level of the contact model. The application of the element with different contact models is shown in three different examples. The end anchorage of a reinforcement bar in a concrete block, the shear transfer across discrete cracks, and the joints of prefabricated wall structures are three examples which show the scale of application of the element.