Solving Image-Based Modeling Challenges with Simpleware and Abaqus

There are many challenges involved when creating simulation-ready models from image-based data such as MRI and CT that can be used in solvers like Abaqus. The time spent on manual segmentation tasks, and the quality of exported meshes to Abaqus, can eat up valuable workflow time, whether you’re using medical, materials, or industrial data. The solutions we’ve developed with Synopsys Simpleware™ software, and explored through partnerships with SSAnalysis, are designed to make it easier for you to overcome bottlenecks and get from your image data to simulation quickly and efficiently.

Overcoming Image Processing Bottleneck

Image data of the body or manufactured parts tend to be very complex, which offers benefits for capturing realistic geometries, but are typically difficult to model with suitable accuracy. In Simpleware software, it is comparatively straightforward to segment and process images for export as models and meshes. We’ve developed a range of semi-automated and automated tools for capturing Regions of Interest. From thresholding and flood fill tools to 3D editing options, we’ve worked on lowering the entry level for getting the information you need from images without having to be an expert.

Figure 1. Example of segmentation of multiple regions of interest from anatomical data

Streamlining Measurements

We’ve also been able to streamline another key challenge of working with complex geometries through measurement and statistics tools. It’s straightforward to generate centerlines, quick measurements (distances, angles), and statistics (volume area), in Simpleware software, which means that you can start analysing your data at an early stage in an image-based workflow.

Integrating CAD and Image Data

If you’re working with image data or even traditional CAD data in Abaqus, then Simpleware software is designed to make it straightforward to create and export models. In the software, you can generate watertight surface and volume meshes with conforming interfaces, ensuring that the exported model in Abaqus is ready to use. We have dedicated exports to Abaqus for this purpose Cutting down on the amount of manual repair needed increases confidence in simulations, whether that’s carrying out patient-specific modelling or working with complex multiphase materials such as rocks or composites.

One of the additional benefits of the software is that you can import CAD data and combine it with image data. This is particularly useful when building patient-specific models including medical devices, as it allows typical workflow steps to be combined within one software, again resulting in a model that’s ready to be used within Abaqus.

Figure 2. Example of CAD positioning

Combining Simpleware Software and Abaqus

There are many examples of Simpleware and Abaqus customers achieving successful workflows. Some of the highlights include the Naval Research Laboratory investigating traumatic brain injury through 3D head models created in Simpleware. Based on MRI data, the whole head model was segmented in Simpleware software and exported as a volume mesh to Abaqus/Explicit for simulating blunt impact and blast conditions. The blunt impact simulations particularly demonstrated good agreement with experimental studies on a post-morterm human subject, with the research informing the development of better military helmets and how the head responds to different stresses.

Figure 3. Head model with helmet in Simpleware software and impact study in Abaqus

Notable work has been carried out by researchers at the University of Padova in Italy. MRI scans of a foot were imported to Simpleware software in order to generate an FE model for analysis of the diabetic foot. The generated mesh was used in Abaqus (v.6.12) to simulate ground support and stiffness values in the soft tissues. Validation of the models was made using experimental data, and showed strong agreement between predicted and measured plantar distribution. This work is now helping with understanding of the aetiology of the diabetic foot.

Figure 4. Meshed foot in Simpleware software and simulation in Abaqus

As well as applications in the Life Sciences, significant research is being conducted by Simpleware and Abaqus users in the materials and manufacturing sectors. Imperial College and University College London use Simpleware to generate meshes of fuel cells from Focused Ion Beam (FIB) tomography containing multiple phases. Abaqus/CAE is used to apply boundary conditions and load cases for stress analysis, enabling predictions of peak maximum principal stresses within different phases when responding to thermal expansion. Understanding these fuel cells, and particularly how electrodes react to heating and cooling, helps with the design and optimisation of materials.

Figure 5. Meshed models in Simpleware software and Abaqus simulation

In addition, work at the University of California Davis into asphalt mixtures use Simpleware and Abaqus to predict the shear modulus of two asphalt mixture types. Internal microstructure for the mixtures was acquired using CT and meshed in Simpleware for shear modulus predictions. The micromechanical viscoelastic FE simulations performed well when using 3D models to approximate laboratory results.

Figure 6. Material segmentation of asphalt mixture in Simpleware software and Abaqus simulation

Conclusions

These applications demonstrate how combining Simpleware and Abaqus reduces the time and stressful workloads associated with building accurate models from 3D image data. Simulation results from these workflows generally indicate how laboratory and experimental testing can be complemented and even reduced by using computational simulation.