Lightweight Materials: Improving Bond Durability with Structural Adhesives
There are many evolving drivers within the automotive industry, however even with the increasing focus on autonomous and electric vehicles, one key area of focus continues to be lightweighting. Reducing weight by just 10 percent can improve fuel economy by six to eight percent.
While high-strength lighter-weight steel grades continue to be used for lightweighting, newer metals with low density, including aluminum and magnesium, are increasing in demand, as are polymer materials such as fiber reinforced composites.
As a result, modern lightweight designs require new bonding technologies to optimize the materials mix incorporated in today’s vehicle structures. Bonding is of special importance because it enables the use of combinations of new materials while providing structural advantages for bonded components that enable design flexibility while enhancing vehicle structural integrity.
Structural Bonding Benefits
- Improved stiffness of car body assemblies
- Up to 25 % increase of energy absorption in the metal structures
- Increased fatigue durability
- Bonding of different substrates possible
- Good acoustic & vibration damping
Structural Bonding Challenges
The joining of steel with lighter-weight materials—from aluminum and magnesium to plastics and carbon fiber composites—is a challenging prospect in automotive bodies. Each of these materials expands at a significantly different rate when exposed to heat in the paint baking cycle, potentially breaking adhesive bonds in joints. Mixed materials have different density properties, and adhesives provide designers the freedom to utilize the most effective lightweight materials for specific applications within vehicle structures. Therefore, a fundamental understanding of load cases for bonded joints and substrates is needed to understand technical challenges, including:
- Addressing thermal expansion
- Adhesion on dissimilar substrates
- Curing speed suitable for large series
Thermal sensitivity and variance of expansion rates prevents standard oven processes and drives bonding processes into the assembly line. Simulation models can drive next generation adhesive requirements for mixed-materials by predicting probable points of failure and failure modes in joints. Paving the way for greater assurance that coefficients of thermal expansion can be managed with application-targeted adhesives.
Henkel’s TEROSON® structural adhesives enable automotive manufacturers to achieve outstanding long-term structural integrity of lightweight materials by optimizing material strength and crash load performance.
Lightweight design is a result of cooperating disciplines, bringing together materials, process and engineering. I’ll be sharing more detailed information and insight to Improve Bond Durability of Structural Adhesives for Lightweight Materials as part of Henkel’s webinar series, Getting the World Where it’s Going. Register now for the September 12 webinar, at 10:00 a.m., EDT to learn more and get your questions answered!