The Dassault Systèmes SIMULIA portfolio releases new versions of its software products every year, and this year is no different. The first release of Abaqus 2017 is now available for download at the media download portal. SIMULIA has developed and broadcast 2017 release webinars to make users aware of new features available in the 2017 release, but those webinars are long recordings ranging from one to two hours each, which can be daunting. This blog post will provide a brief highlight of materials and explicit updates in Abaqus solver 2017. A more detailed explanation of any mentioned update, or answers to further questions, can be obtained either by listening to the webinar recordings at the SIMULIA 3DExperience user community portal, leaving a comment on this post, or contacting us.

SPH boundary conditions improvements

SPH particles located on opposite sides of a surface cannot interact with each other in the absence of boundary condition. This was not the case in previous releases; in Abaqus 2017, this is the default boundary condition setting. There are further improvements in tensile instability control to prevent instability among particles subjected to local tensile stresses. Below is an example in which there are SPH particles in two different chambers; the lower chamber particles are subjected to displacement BC while upper chamber particles are not subjected to any BC.

DEM improvements

1. The series and parallel search algorithms for contact are unified to improve the DEM performance. The search cells are created only once.
2. It is now possible to run DEM jobs with particle generators in parallel mode. This means more than one particle generator can be active while a DEM job is running.
3. In previous releases, only fixed time increment scheme was available and it was difficult for the user to predict the appropriate time increment. In the 2017 release, an automatic time increment scheme has been introduced.
4. Adhesive particle mixing is now supported. The algorithm used is called JKR adhesive inter particle contact. Both Hertz contact and friction are supported.

Material Enhancements

1. There is some good news for users in the health care industry who design and manufacture cardiovascular stents: Super-elasticity, which was previously a part of user subroutines, is now available in the Abaqus 2017 material library. The motivation is Nitinol, a nickel titanium alloy used in cardiovascular stents because of super elasticity, shape memory effect, biocompatibility, and fatigue. The Nitinol model exhibits linear elastic Austensite behavior at lower stresses. On further loading, transformation from Austensite to Martensite occurs but behavior is still linear elastic. Beyond full transformation, Martensite exhibits elastic plastic behavior. A similar phenomenon is observed in compression loading. It is supported in Abaqus CAE.

 

 

 

 

 

 

 

 

 

 

2. A multilinear kinematic hardening model is now available in Abaqus 2017. In previous releases, this model was available as a user subroutine material called ABQ_MULTILIN_KINHARD.  Plasticity follows an array of perfectly plastic subvolumes that follow Von-Mises criteria, each with a unique yield strength. This model offers more flexibility than the linear kinematic hardening model. It is available only in Abaqus standard and intended for thermo-mechanical fatigue of metals. It is supported in Abaqus CAE.

3. The definition of damage initiation and damage evolution of cohesive elements with traction separation response has been enhanced to include rate dependent cohesive behavior. It is available only in Abaqus explicit. Non-linear damage initiation of ductile metals is now supported in Abaqus 2017. This model provides more flexibility to predict damage under arbitrary loading paths. It is available both in Abaqus standard as well as in explicit for ductile, shear and Johnson Cook material models.

 

4. Non-linear damage initiation of ductile metals is now supported in Abaqus 2017. This model provides more flexibility to predict damage under arbitrary loading paths. It is available both in Abaqus standard and explicit for ductile, shear and Johnson Cook material models.

5. The parallel rheological framework model now supports plane stress elements as well, in both standard as well as in explicit.

6. A new subroutine for user defined thermal expansion coefficients has been introduced. It is called VUEXPAN. This routine can be used in explicit to define thermal strain increments as a function of temperature, time, element number, state, or field variable. It is available only with Mises plasticity, Hill Plasticity and Johnson Cook model.

Usability Enhancements

1.Enhancements in distortion control: In Abaqus explicit, it is possible to convert highly compressed solid elements to linear kinematic formulation. Once that happens, the analysis does not stop even if the elements get inverted. It is activated by default when solid elements are used with crushable foam material.

2. Larger stable time increments in Abaqus explicit: In Abaqus 2017, there is an improved estimate method of element characteristic length to get larger stable time increments. It is defined in explicit step as follows:

*Dynamic, Explicit, improved DT method=YES (by default) or NO

It is further possible to invoke this method selectively in individual sets instead of global model as follows

*section control, improved DT method = YES or NO