Modular Assembly of Body Structures for Mass Transit Vehicles
David Tobler
Strategic Director Marketing Transportation & Marine Business | We help engineers to improve vehicle design and production with adhesive bonding | Sika
The automotive industry is the master in modular and just-in-time assembly. Many brands offer almost endless options to consumers for customizing their new cars. In modular assembly, manufacturers can choose to produce modules offline either by themselves or by outsourcing the unit's production. I like to introduce a few cases from the commercial vehicle industry where modular assembly is helping manufacturers to simplify and optimize mass transit vehicle assembly.?
I also like to point you to our new Youtube Podcast, "Better made with Adhesives." In the first episode, we get insights into the design and assembly at eVersum mobility solutions , a Slovenian manufacturer of electrical eShuttles and eTrains; watch it for details.?
Modularity in Bus Manufacturing
Most buses are still manufactured based on a steel frame that is plated with the outer steel skin. Typically front and rear masks are made of composite to allow unique and aerodynamic style. Advanced bus manufacturing practice is often based on modular assembly.?
eVersum mobility solutions designed their eShuttle and eTrains with frame modules, which are combined to reach vehicles of different lengths and designs. The outer skins and masks are made of composite materials. The frame modules and composite parts can be manufactured by third parties, avoiding investments in bodywork and painting in the assembly plant. During assembly, the different modules are joined by mechanical fasteners and adhesive bonding.
Lightweight Roof Module
The RV industry uses sandwich panels as outer skins for caravans and motorhomes. They are pre-manufactured offline, lightweight, insulate the interior compartment and provide the necessary structure. The EU Litebus project explored the use of sandwich panels in bus design (link below). Nowadays, several bus manufacturers use roof and floor modules made of sandwich panels in their bus assemblies. The modular approach allows the entire roof structure's preassembly, e.g., the air conditioning unit or luggage racks. Since no structural reinforcement in the sandwich panel is needed, 25% and more in weight reduction can be achieved compared with the traditional design.?
The bus is assembled from the modules using structural adhesives that can bridge tolerances. SikaForce-803 is an ideal solution due to its long pot life and fast-cure performance. It is also permanently elastic to avoid stress from the thermal expansion of the different materials.?
SikaForce-803 brings together the advantages of both elastic and structural adhesives. It provides the highest levels of strength retention in high service temperatures combined with lasting elasticity at low temperatures. This makes it the best choice for bonding materials with different thermal expansion coefficients.
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SikaForce-803 allows customers to consider new design possibilities and aesthetics that involve mixed and composite materials while maintaining body rigidity and good elasticity – ideal mechanical characteristics. Like for many products, Sika provides a material card, including a calculation model on request.
Structural sandwich panels can also be used for floors and side panels, reducing the required structure and weight and enabling a modular assembly process. The SikaForce-803 and fully bonded sandwich roof were developed in cooperation with 3A Composites Mobility to combine light weight with optimal assembly.?
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References:
Promoting IR Solutions and Support For Excelitas Noblelight UK Neston Wirral CH64 3UZ
1 年Heraeus UK likes. With trials IR has been used to fast cure the bonding material. For case study please ask. ??
Produktentwicklung at 3A Composites
1 年Efficient modular production starts with good cooperation and a common understanding between partners like SIKA and 3A Composites Mobility. Thank you David.
Strategic Marketing Manager Transportation Americas | We help engineers improve vehicle design and assembly processes with adhesive bonding | Author of "Adhesive Engineering Insights" Newsletter
1 年The commercial vehicle industry increasingly focuses on modular assembly and industry 4.0. Both go hand in hand, as it allows for standardized processes, a switch from manual to (semi-)-automatic application, and the use of much faster assembly adhesives to speed up the production line resulting in significant cost reduction and (process-)quality improvements. Modular builds will also become a hot topic enabling further sustainability improvements. Great article, David!
Head Industry Sweden
1 年Nice presentation