A user programmed cohesive zone finite element for ANSYS Mechanical

Abstract

A cohesive finite element implemented as a user programmable feature (UPF) in ANSYS Mechanical is presented. Non-standard post-processing capabilities compared to current available cohesive elements in commercial finite element software packages have been defined and implemented. A description of the element formulation and the post-processing options are provided. Simulation studies are presented which serves to verify the implementation and compare the performance to ANSYS INTER205 cohesive element. The results show that the implemented element performs better in terms of ability to converge to a solution and requires fewer iterations to converge in the incremental Newton-Raphson solution procedure used. Additionally, a sensitivity study about the typical remedy to obtain convergent solutions having coarse meshes by lowering the onset traction is conducted. The study brings new insight to the effect of lowering the onset traction and recommendations of practical usage in case of coarse meshes are outlined.

Durability Assessment of Composite Structural Element Reinforced with Fabric due to Delamination

“…In the second phase, after exceeding the threshold value of force F R A(0) =F R II =134 N, the tensile stiffness of fi nite element was reduced in three steps, which went down to reducing cross-section A R(0) to a value close to zero (the roving section was broken) in accordance with formulas (10), (11) and (12). However, each cross-section reduction was accompanied by an increase in the initial threshold value of force F R A(0) in accordance with formula (8).…”

“…However, such a modeling method can cause erroneous simulation results [7,8], and simulating delamination with its help requires the use of special computational methods (e.g. VCCT [9], cohesive zone method [10]), which signifi cantly reduce the numerical effi ciency of the model and require predicting the location of potential damage sites.…”

Simulation of Delamination in a Composite Using a Shell-beam Mesoscale Finite Element Model

“…The consequence of this assumption was the adoption of the mesoscale laminate model, which is a satisfactory compromise between the level of detail reflecting the internal structure of the laminate and the numerical efficiency of the model. Since in the engineering calculations of real laminate structures it is difficult to predict the location of the crack initiation site in advance, the previously described delamination modelling techniques using the finite element method, such as VCCT MECT - (Figure 7.b [9, 10], debonding [11,12] or the cohesive zone [13,14], were rejected.…”

“…A similar assumption is used in the cohesive zone method, which most often involves the use of an 8-node finite element of the cohesive type, binding adjacent layers of the laminate modelled [13,14]. Application of the contact debonding method with the cracking model and the cohesive zone method requires defining the relationship between stresses and nodes displacements for the elements modelling the cracking zone.…”

Finite element model of laminate construction element with multi-phase microstructure

“…Simulation of crack initiation and propagation in the macroscale model is possible through the use of special computational methods, e.g. the VCCT technique [11] or the cohesive zone model [12]. With this purpose in mind, special node bonds are defined between layers or additional cohesive elements are introduced at the site of a potential crack, which is equivalent to the need to predict the site and size of the crack.…”