When producing a part, you want it to match the design, the geometry. How to achieve this is not always evident.

For example, when the part is created from sheet metal by pressing it between an upper and lower die, the final part may not fully match the space in between the dies due to the spring back effect. If the deformation would be fully plastic, then the deformed shape will not change during unloading. If it is partially elastic, then the elastic deformation is recovered upon unloading and hence the final shape differs from the shape between the dies. In this blog I’ll give an example of this effect, showing that we can model it with Abaqus.

Sometimes you may wish to simulate a process where various parts interact with one another. In such cases it is often impossible to rely on predefined loads and boundary conditions, since the exact points of contact are dependent on the solution. Including contact in your simulation can be a more realistic way to represent loadings.

Abaqus provides a wide range of mechanical models and numerical methods for contact. We will begin this month’s webinar with an overview of these capabilities, considering how to select the best options for a given problem. We will then move on to some challenging example problems and investigate how advanced features of Abaqus contact can help convergence and ensure you obtain realistic solutions.

In this blog post, we will be showcasing a fully coupled fluid structure interaction (FSI) analysis, of a peristaltic roller pump. This study will focus on assessing the performance of a peristaltic pump, under operation. This co-simulation analysis, will solve for both the structural and fluid domains' unknown quantities, during 1 revolution of the rotating mechanism of the pump.

This is an example of a challenging application, in which numerical modelling and computer simulations can provide a lot of insight and value.

The aspects we want to evaluate in this digital model are; determining the volume flow-rate for a given rotation speed, assessing contact stress areas on the tube, and determining the torque output for the given rpm.

Today I have came across a very inspiring video.

It contains a lecture of Dr. David Hibbitt, founder of the Abaqus software, held on 24th of may 2019 at MIT, department Civil and Environmental Engineering. The lecture was called; "ABAQUS and its market:  evolution of an engineering simulation software venture."

If you have an hour left during the day / evening, sit back, relax and watch this inspiring lecture, where Dr. David Hibbitt goes through the actual start-up phase of the Abaqus company until today.

To model the behaviour of rubbers and rubber-like materials, typically hyperelastic material models are used. A hyperelastic material is elastic: after unloading, the material returns to its original shape. The material state therefore does not depend on the history or the rate of deformation, but only on the current loading. The model is based on a strain energy potential, which is a function of the (invariants of the) current strain.

In this blog post, we will be discussing the differences between the kinematic and distributing constraints in Abaqus. The differences between these types of constraints will be highlighted in an example model.

Introduction and Usage

Surfaced based coupling constraints are used in Abaqus for the following purposes:

Let’s start with a problem:

“A ladder hangs over the side of a ship anchored in port. The bottom rung of the ladder touches the water. The ladder is 30 cm wide and 270 cm long. The rungs are 1 cm thick and the distance between them is 34 cm. If the tide is rising at a rate of 15cm per hour, how long will it be before the water reaches the top rung?”

It happens all the time. Too often we still see companies that trust on simulations being performed with a solid-mesh, while the geometry is thin walled, like with sheet-metal, extruded parts or plastic parts. If you ask the people why they didn’t use a shell mesh, most of the time they will tell you it will take too much time to generate a mid-surface shell model, or they think it is not feasible capturing the necessary detail in the analysis, so they decided to just ignore the rules.

Below we have listed why creating a mid-surface shell model is still favourable.

The Challenge

A plastic High Density Polyethylene container is supposed to protect its contents, in some cases even when it falls. To test this, drop tests are performed. The contents of a container can influence its behaviour during a drop test.

With Abaqus Explicit, it is possible and quite straight forward to simulate a container with water in it using a CEL approach. But what if the container contains sand, stones or pallets, which consists of small particles? How can we model this? Sand can flow, similar to fluids. But it can also pile up, something fluids will not do. There are different approaches to modelling it thinkable, depending on the intended application. In this case, we will investigate the use of Abaqus’ discrete element method (DEM) for this purpose even though the CEL approach could also be used for that. DEM is a relatively new technique in which particles are individually modelled.

In this blog we will focus on the capabilities of Simulia Abaqus to assist in modelling rubber like materials.
Rubber materials such as thermoplastics are largely used in the industry; to list some of the areas where these materials can be found we can mention tyre industry, consumer pack goods, medical or sealing solutions but rubbers are also present in many others engineering fields. Today I will dedicate the next lines to the sealing market due to its beneficial ratio between ease to explain-build up a model and the high end capabilities that Abaqus can provide.