Thatcham, the automotive research centre based in the UK, provides a range of products and services to the insurance and motor repair industries.
Thatchamnet provides online access to its tried and tested repair methods. Every detail is included in each new method to ensure crash repairers are aware of the challenges brought about by new technologies and modern designs, and are provided with effective solutions.
Moving away from
traditional techniques
Increasingly, the evolution of car design with regard to occupant safety, and recent emphasis on pedestrian safety, has taken construction and panel joining further and further away from traditional techniques. In addition, material and production constraints have led to the inclusion of laser welding to reduce seams, and the use of bonding has become far more common.
High Strength Steels are commonly expected now by repairers, though steel technology is still developing, with an individual panel possibly made with more than one property and tensile strength. Structural load paths, particularly those designed to absorb and direct side impacts, result in panels overlapping in specific ways so that the combined strength of panels absorbs the force.
Mazda 3 developments
One recent example can be seen in the construction of the Mazda 3. This vehicle has evolved from a Ford platform but has undergone complex structural changes. Indeed, many of the panels may look the same as the Ford equivalent, but there are structural changes, including material changes and/or reinforcers added specifically to the Mazda panel.
The side sill reinforcement panel is one such panel that is constructed of high strength steel, further reinforced invisibly behind (between the reinforcement and inner sill). There is nowhere on the sill that can be safely sectioned, so complete replacement is required.
However, the ‘B’ post reinforcement and ‘A’ post reinforcement panels overlap the sill reinforcement. Therefore, they require removing to allow this.
Consequently the outer ‘B’ and ‘A’ posts need removing, requiring removal of the facia instrument panel, the front screen, the front wing, headlamp and bumper.
The dogleg panel will require removing from the rear, probably with quarter glass. Add in the required painting and colour blending and this becomes a very large job for what could have been assumed as a small localised repair to the sill and reinforcement.
It is not inconceivable that someone may attempt to section the ‘A’ and ‘B’ post reinforcements; however, this would create a weak spot on a HSS panel that is designed to link with and share strength with the sill reinforcement. It is also conceivable that an attempt could be made to section the sill reinforcement itself, but it is constructed from 590MPa UHSS, with further reinforcements behind.
While it may appear possible to simplify the repair, this could compromise the future side-impact performance of the vehicle. Thatcham data is designed and continually refined to protect the repairer from making such mistakes.
