Validating the accuracy of new vehicle dimensions and achieving a repeatable, resilient, and dependable Body-in-White (BIW) during and after launch requires a delicate balancing act between the reality of a dispersed supply chain and ambitious timeframes. Assemblies, subassemblies, and individual pieces are shipped to the body shop, where they must assemble within the specified design tolerances.
What does BIW entail?
The term BIW is used to describe a vehicle once all its body panels have been assembled using various methods such as welding (MIG/MAG, spot), riveting, bonding, clinching, laser brazing, etc. BIW refers to a vehicle’s unfinished frame before any finishing touches have been added, including paint, the engine, any chassis sub-assemblies, or any trim (glass, seats, door locks/handles, electronics, upholstery, etc.).
Major Influencing Factors of BIW Design
- Number of parts
- Internal structural reinforcements
Features of BIW Design
- Effective load routes in the BIW Fixture Design architecture with a few components are fundamental design principles that must be adhered to when creating a BIW.
- BIW material distribution, taking into account bending and torsional rigidity.
- The potential for an effective performance boost from an internal reinforcement placement.
- A complete vehicle crash study using a material optimisation technique.
Materials Used in BIW
- Body-in-white (BIW) constructions of production cars primarily use high-strength steels and other ferrous materials.
- Using stronger steels with superior forming qualities allows for narrower gauges and further weight reductions. Using mixed steels of varying thicknesses in custom blanks has revolutionised lightweight design. In addition to BIW Design, alternative materials for automobile parts have increased in recent years.
- Metals like aluminium and magnesium, as well as fibre-reinforced polymer composites (FRPCs), fall under this category. All of these shifts necessitate fresh approaches to connecting materials.
- Recent years have gradually replaced mild steel grades with higher-strength steels, particularly in the heavier load-bearing and crash-resistant areas of the BIW. It has been achieved through ultra-high strength steel (UHSS).
- The ULSAB project is only one example demonstrating how UHSS can be used in the BIW to make the vehicle safer, lighter, and stiffer at a reasonable cost.
- BMWs built from the aluminium account for roughly 34,000 metric tonnes of aluminium yearly. Because of the high cost of the material, they are primarily used in the automobile market’s smaller volume, higher value sector.
- The automotive industry has three top research priorities related to aluminium alloys. The first is to strengthen aluminium alloys to produce thinner sheets. The next step is to regulate their formability, and the final step is to fortify the material against impacts.
- Die-cast magnesium alloys have replaced metal in specific automotive body components, including interior panel stiffeners. Traditional advantages of magnesium alloys over aluminium alloys include lower melting temperature, lower density, and lower corrosion resistance.
- They are difficult to weld, but other joining methods, such as adhesive bonding or mechanical attaching, make assembly much more straightforward.
In the case of Fiber Reinforced Polymers (FRP), joining the composite pieces is accomplished through the joint’s design, with inserts joining the components before they are co-cured. Alternatives include mechanical fastening and adhesive bonding.