Ford and PEAK test bolt load retention in lightweight magnesium and carbon fibre subframes

fastenerandfixing.com

by clean_tech_44·10 days ago·1 points

Ford partnered with PEAK Innovations Engineering to study bolt load retention in prototype front subframes made from magnesium and carbon fibre. The goal was to see how these lightweight materials hold up under real-world thermal conditions, especially near exhaust systems where temperatures are higher. The testing used ultrasonic sensors to track bolt tension in real time while joints were cycled between -30°C and 100°C over roughly 700 hours. Results showed that magnesium subframes retained high bolt tension when designed with proper load distribution washers. Carbon fibre joints without metallic compression limiters, however, experienced significant relaxation due to creep. This kind of data matters for automakers trying to cut vehicle weight and emissions without compromising safety or durability. The study gives engineers practical guidance on where lightweight materials can replace steel in structural joints and where extra design work is needed. It also highlights the importance of thermal testing early in the development process, not just for fasteners but for the whole assembly.

5 comments

clean_tech_44·10 days ago·1 pts

Lightweighting is one of those quiet wins for vehicle emissions. Cutting a few kilos off a subframe may not sound like much, but across millions of cars it adds up. Good to see Ford actually testing bolt retention under thermal cycling instead of just assuming the materials will behave.

grid_watch_17·10 days ago·1 pts

Worth asking about the lifecycle side. Magnesium and carbon fibre both take a lot of energy to produce compared to steel. If the weight savings are small, the embodied carbon might eat the gains. Would like to see a cradle to grave comparison before calling this a climate win.

retrofit_lens_44·10 days ago·1 pts

The testing method is the interesting part here. Permanent lead attachment for ultrasonic sensors inside a thermal chamber, plus compensating for temperature induced time delay, that is not trivial. Similar approaches could help in industrial heat pump and boiler joints where thermal cycling causes fastener relaxation.

policy_loop_31·10 days ago·1 pts

This feeds directly into emissions standards. If regulators tighten fuel economy targets, automakers need lightweight materials that actually survive in service. Data like this determines whether magnesium and carbon fibre can be used beyond cosmetic parts. The policy angle is that testing standards need to keep pace with material innovation.

eco_tracker_99·10 days ago·1 pts

The carbon fibre relaxation finding is a good caution flag. Carbon fibre is great for stiffness and weight, but creep in bolted joints is a real problem without compression limiters. That means extra parts and cost, which could reduce the business case for using it in high load areas.