NRC experts in blow molding are helping the transportation industry shift to hydrogen-powered vehicles

Over the last 3 years, a team of experts in digital manufacturing from the NRC's Automotive and Surface Transportation Research Centre developed a new and unique blow molding simulation model to help vehicle manufacturers design ultra-resistant hydrogen reservoirs through a more effective and low-cost process. Conducted as part of the NRC's SIGBLOW blow molding simulation research group, this project was made possible with funding from Natural Resources Canada.

Benefitting from digital technologies

As the ground transportation industry transitions to cleaner energy sources to meet net-zero carbon emission targets, manufacturers are challenged to find new ways to adapt and improve vehicle design and production processes. Two key solutions to meet those targets are adopting new energy sources for medium- and heavy-duty vehicles, such as hydrogen, and reducing the weight of these vehicle to help lower their energy consumption. By using digital manufacturing, vehicle makers are now able to move away from the traditional physical testing and can instead benefit from the many advantages of digital simulation, such as reduced costs and waste and decreased production turnaround times.

Meeting the hydrogen challenge

Major producers of vehicle fuel tanks have now oriented their research and development toward rethinking how they manufacture hydrogen reservoirs for vehicles, namely by switching from steel to polymer. Compared with a standard vehicle fuel tank, a hydrogen reservoir has a longer shape. In addition, because hydrogen has a very low density under normal conditions and is compressed to increase the amount of hydrogen stored, the reservoir is subjected to extremely high pressure. These unique characteristics result in new fabrication issues like how to ensure a consistent thickness throughout the tank liner while conforming to regulatory standards for leakage. Because existing digital simulation models were not developed to take these critical characteristics into consideration, NRC experts took on this engineering challenge using the NRC's BlowView blow molding simulation software. BlowView is the world's leading simulation software for blow molding and thermoforming, developed for designing and optimizing thermoplastic components.

Improving the design process of hydrogen tanks

BlowView is the only software that can simulate and optimize the process for manufacturing hydrogen tank liners. As a result of this three-year project, the NRC developed and implemented a digital model to simulate and control the distribution thickness of tank liners at different steps of the blow molding process. The model was also used to predict the hydrogen permeation through the reservoir wall. This rigorous, multi-step method allows for accurate predictions and ensures that the final product meets resistance and sealing performance requirements. The use of such predictive tools is critical for obtaining the required level of quality and consistency on every reservoir liner produced.

"We're building on over 30 years of expertise in computer modelling of blow molding applications and extensive scientific knowledge of polymers to develop new models and expand the BlowView software capabilities to support the industry," says Florin Ilinca, team lead of simulation and numerical modelling at the NRC's Automotive and Surface Transportation Research Centre.

The new BlowView capabilities developed for this project provide the ability to confront sustainability issues by optimizing product design and finding new ways to reduce material and energy usage. It allows users, mostly vehicle engineers in this case, to predict hydrogen leaks before the tank liners are put into production, avoiding repetitive, time-consuming and wasteful trial-and-error steps of traditional design processes.

The versatile BlowView simulation software allows manufacturers to test new material and to improve vehicle design by building lighter and stronger parts leading to weight reduction of the vehicle. Zohir Benrabah is a research officer at the research centre and says, "Current hydrogen reservoirs are made of steel. Switching to polymer will result in a significant weight reduction and lower the fuel consumption of vehicles."

Supporting a greener future with BlowView

As the project advances, the NRC will work closely with its industry partners to validate the extended capabilities of BlowView and advance adoption of type 4 hydrogen tanks. Current research focuses on exploring novel materials, optimizing the production of larger-sized hydrogen reservoirs and addressing challenges such as delamination of liner composite, liner damage and buckling encountered during repeated pressurization–depressurization cycles. Within the SIGBLOW industrial R&D group, NRC experts will continue to drive innovation forward as the automotive, packaging and resin manufacturing sectors increasingly develop environmentally friendly technologies.