"The underlying driver of the need to reduce CO2 emissions is here to stay."

In the lead-up to our first Lightweight Chassis & Frame Design conference in May, we interviewed Dr. Kevin Lindsay, Technical Director at FAR-UK, about carbon fibre composite vehicle frames and how to achieve crash performance and structural efficiency.

Dr. Lindsay, what is your role at the FAR-UK and where do you set your focus in research?

I am Technical Director at Far-UK. Our main focus is on the development of cost effective low weight structures. In particular we are passionate about weight saving leading to CO2 emissions reductions. As part of this we have aligned ourselves with the transport sector and look to find ways of reducing the cost of composites to allow further market penetration.

Where do you see the current main challenges for automotive lightweight chassis and frame design and how can those be addressed?

The main challenges at the moment are costs and consistent quality. Production volume is not really an issue, for instance we can go to multiple tool sets, but this has implications for costs and potential component variability. The techniques that we are using to address these areas are process development and automation. We also spend a significant amount of time in design.

This allows us to minimize the amount of materials that have been used, in particular the carbon fiber content, this also helps reduce the overall costs. Materials wastage is also important, especially for expensive carbon fibers, so we have developed methods for making composite structures that almost eliminate materials wastage during processing.

What are the advantages of carbon fiber composite vehicle frames and where do you see still space for improvement?

The primary advantage is the weight saving potential, we often realize 50% to 60% weight saving compared to complete steel structures. There are some secondary benefits too. The vehicle market is fragmenting, meaning that production volume runs are getting smaller. Add into this the emergence of new vehicle types and even new manufacturers, carbon fiber may be an enabler for these types and companies to get into production. As before we must do this at a cost that enables the vehicles to be produced.

At what extent can structural stability be guaranteed during crash?

Safety is always a given requirement. The first part is that we design the passenger cell to withstand the impact loads that are developed during crash and then we need to manage the crash impulse. Maintaining the structural stability is at the heart of our design process. We have developed a materials structure, Axontex™, which is exceptionally stable in crash due to the internal cellular structure. This patented process allows the manufacture of stable vehicle structures.

"Data gathering for crash models" plays an important role. How difficult is it to gather those data and how do you apply them to your crash models?

The gathering of materials data has always been a difficult process that has caused disagreements within our community. We have developed a process that back calculates data from coupons and beam tests which is then validated against vehicle structure; this is the basis of what we do.

What are the requirements for carbon fiber composite vehicle frames? How can they be fulfilled and where are the limits?

The requirement for vehicles has been developed over a number of years. In general our industry knows what is required to develop the vehicles that people want. This defines what we must do from a functional package, we just need to do that at a significantly lower weight. The limits are still being explored.

How can one ensure maximum driver and passenger safety in lightweight vehicles?

As before, safety is our main concern. Understanding vehicle safety has been one of the major developments in our industry over a number of years. This has led to the development of stringent legislative crash tests that define, for instance, occupant injury criteria. Our main driver is meeting these requirements, demonstrating this through crash analysis and validating this through testing.

Where do you see the future of lightweight chassis and frame design?

This is an interesting time in our industry. Many companies are trying a range of different vehicle architectures and ways of producing vehicles. The underlying driver of the need to reduce CO2 emissions is here to stay. It is imperative on our industry to come up with a cost effective solution to weight reduction to enable this CO2 emissions reduction.