P-957P-957

P 957 – Numaerical simulation of adhesive joints with elasto-plastic and fracture mechanical cohesive elements

30,00

SKU: 011f628e7b6a Category:

Description

P 957 – Numaerical simulation of adhesive joints with elasto-plastic and fracture mechanical cohesive elements

The rapid development particularly in the automotive, aerospace and railway industry and the numerical safety studies for individual components and structures needing simulation methods with high forecasting quality. These must also be able to predict the mechanical behavior of bonded joints with toughened adhesives, until the failure of the joint, safely and efficiently. For the numerical simulation of the mechanical behavior of large bonded structures, such as automobile bodies, so-called interface elements are used for reasons of efficiency. The analysis of bonded joints with structural adhesives mentioned above leads to a elasto-plastic model of continuummechanics or a fracture-mechanical model approach. A requirement for the use of these elements is the experimental characterization of the adhesives. Therefore, in this project, both continuum and fracture mechanical investigations were carried out.
In addition to the creation of additional material cards was the objective of the present study to figure out whether the basic experiments can be applied to other adhesives of different type and whether they are applicable to other adhesive layer thicknesses. Therefore from previous projects already known testing concepts are used to study the adhesive layers under uniaxial stress. To determine the continuummechanical characteristics the thick adherent shear test specimen and butt-joint specimen and for the fracture-mechanical parameters the tapered double cantilever beam specimen and variations of the end-notched flexure-specimen are used. To investigate the continuum-mechanical behavior of adhesive layers in multi-axial load cases the butt-bonded hollow cylinder specimen was used. To investigate the fracture-mechanical behavior in mixed mode load cases, an experiment was carried out in which the mode ratio is controlled during testing. Three different adhesives were analyzed with up to three adhesive layers thicknesses and three strain rates. The modelling of tough modified adhesives on the basis of fracture mechanics and theory of plasticity with damage enables a clear replacement for detecting effects that macroscopically evident in increased or reduced dissipation. The modelling of toughened adhesives on the basis of fracture mechanics and theory of plasticity with damage enables an analogous modelling without layer-thickness-effects that macroscopically
appears in increased or reduced dissipation. For the numerically efficient modelling of the macroscopic behaviour under quasi-static and dynamic (crash) load a elastoplastic interface model is used. Besides the parameter identification and verification of basic tests a validation of the model takes place with specimen of homogeneous and inhomogeneous stress state. The T-joint, uses as a similar-component validation specimen, shows the accuracy of the model under practical conditions.

Published in:
2015

Authors:
Prof. Dr.-Ing. G. Meschut, Prof. Dr.-Ing. B. Mayer, Prof. Dr.-Ing. A. Matzenmiller