Interview: Prof. Naoki Takano of Keio University on Using Simpleware Software to Analyze and Simulate Microstructures to Improve Manufacturing Quality and Medical Care

Posted on 24 October 2022 by Jessica James

 

In this interview, our Japanese resellers JSOL spoke to Prof. Naoki Takano of Keio University to learn about how they use Synopsys Simpleware and create 3D models of actual products used in manufacturing and medical care.

Prof. Naoki Takano
Department of Mechanical Engineering, Keio University, Japan

How uncertainty simulation is changing the manufacturing industry and medical care

"Futashikasa" in Japanese refers to "uncertainty". One of the research themes of Prof. Takano, Department of Mechanical Engineering, Keio University, Japan, who mainly researches computational dynamics, is “developing simulation of uncertainty and a study of the validity confirmation”. This research is expected to contribute to production fields, including additive fabrication manufacturing utilizing 3D printers and design structures of multiple materials. In addition, the research enables the further analysis of different biomedical tissue for an individual, as well as biomechanics studies in the medical-engineering field. 

For the manufacturing field, there are increasing cases where a prototype at the design and development stage is formed by 3D printing. This move is due to trial products with 3D printers being more efficiently formed at a lower cost, and also in a shorter timeframe than with metal molding. However, according to parameter settings, variations in quality and strength occur when one component is generated, even though the same 3D CAD data was used. Industrial products which seem to be created uniformly actually contain individual differences.

Prof. Takano therefore images actual parts made by 3D printers through Micro-CT and MRI, and obtains image data from them. He then reproduces the parts as virtual 3D models, and simulates their unevenness and uncertainty. He analyzes the factors which influence strength, and attempts to improve the quality of industrial materials such as fiber-reinforced plastics and metal materials, as well as biomechanics such as implants targeted at teeth and bones.

What are the benefits of using Simpleware software to convert image data of actual products through CT and MRI CT into a 3D model?

Prof. Takano: "Although CT and MRIs have the advantage of handling three dimensions unlike electronic microscopes, the acquired image data is just a two-dimensional image, a so-to-speak cross-sectional image. However, recognizing a subject in two dimensions is totally different from in three dimensions."

For instance, it is hard for micro-information about composite and porous materials to grasp the real image without acquiring three-dimensional images. If there are voids inside, the diameter of the void is hardly recognizable since it would change according to the cutting method of the cross-sectional image.

Synopsys Simpleware software enables creation of three-dimensional models from cross-sectional images of CT and MRIs through the processing of segmentation and filter tools. It also allows measurements of the structure of geometry, length and angle, mixture volume, and porosity. JSOL in Japan sells the software as an official distributor and provides a support service.

Pursuing uncertainty to ensure the reliability of simulation

The beginning of handling "uncertainty" for Prof. Takano dates back to the 2000s. At that time, "how do we secure the reliability of simulation?" was a big theme, and he had been exploring the standard procedure of the subject. The study of uncertainty was required to enhance the reliability. Analysis that includes uncertainty was required to simulate three-dimensional models on computers, rather than handling real products. In around 2019, he started to utilize Simpleware software for this purpose.

How has been your experience with using the software?

Prof. Takano: "I was surprised to know there were some unexpected fabrication failures even though 3D printers were used. I sent the CAD data, which included the design drawings, to several companies and asked them to form the model, then I found out that the way of making the product was clearly different depending on the company. Then we became interested in what kind of differences were made in the output and what the factors were. So, I decided to measure them using Simpleware software. The software can create three-dimensional models and measure the size of any parts, so I think it is an outstanding software for the industrial field too."

Analyzing effects on medical equipment and fatigue life

Prof. Takano has also widened the range of utilizations of the software in both manufacturing and medical fields. In Keio University, where Prof. Takano works, researchers often conduct their study in cooperation with the other departments. Prof. Takano’s membership of the Faculty of Science and Technology includes cases of medical-engineering collaboration. This collaboration is particularly important for the medical field, since the object is the human body which varies per person, and there is a strong need for custom-made medical equipment and high expectations of 3D models. In this respect, Prof. Takano assumed Simpleware software would be adequate for these needs, particularly in cases where technical terms differ across departments. For instance, there are various software which handle the human body as three-dimensional models in medical field, and they use specific names based on a shape of bone to show three-dimensional directions. On the other hand, in the engineering field, X-Y-Z axes are used.

How does Simpleware software help with these types of engineering and medical challenges?

Prof. Takano: "When we talk with someone who belongs to a different department and we use different technical term meanings for each other, the confusion may occur in our communication and cause mistakes. So, if we use a software in medical-engineering collaboration, I think Simpleware software is easy to use because it has X-Y-Z axes for direction which is familiar in engineering field." Simpleware software also provides high-quality three-dimensional model of the human body with complicated structures. When modeling something which has many curved lines, for example, a partial denture, the curved features become jagged based on voxels and it also cannot be measured precisely. Simpleware software, however, makes it possible to measure the detailed parts such as subtle curves. 

The software also enables collaboration with other analysis tools. For instance, an aligner for orthodontic treatment is formed corresponding to shape of each mouth and tooth, therefore they differ from each other in thickness of each part. It is useful to know with simulation what kind of force would act on what part of them and how correction of teeth alignment would progress, and also how many times a partial denture can be put in and taken off. For example, Prof. Takano is thinking of utilizing the software by using it with "Ansys LS-DYNA", a software which excels at impact and structure analysis for something non-linear. Ansys LS-DYNA is also one of the JSOL products and the collaboration will enable us to perform from CT imaging to simulation in succession.

Use of 3D printing and analysis for different parts

Support from JSOL

When using Simpleware software, the support from JSOL was effective. One of the supports was scripting that allowed Prof. Takano to efficiently perform statistical measurement process for enormous amounts of image data. JSOL prepared the script that makes it to export CSV with repeated measurements of multiple areas. 

Prof. Takano: "If my students take multiple measurements on PC, clicking so many times, then it will take an immense amount of time and also make them physically tired. Using the script by JSOL makes it easier to obtain measurements. You can just wait for and get the results, then export it as a CSV file. Meanwhile, we can spare more time for research."

How can structural observation of the micro-world and research into uncertainty simulation be a strength for Japanese companies?

Prof. Takano: "There should be a large amount of failure cases in design and development site where they probably repeat by trial and error. By creating a database from such things on simulation and making them visible, we should be able to generate a database of intelligence and knowledge by stochastically handling the data, including generation probability. In materials and biomechanics fields, there are many cases where you cannot observe the cause of unevenness to micro-structure without using the CT. If we offer a method capable of using simulation by Simpleware software as a routine workflow in design and development departments in Japanese companies, the strength of observing micro-structures can permeate the industry."

Miyazaki Miki, JSOL (left) and Prof. Naoki Takano, Keio University (right)

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