USM Research to Make Cars Lighter, Cheaper and Cleaner

By Assoc. Ir. Dr. Ahmad Baharuddin bin Abdullah

November 2022 VOICES OF USM
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TAKE A DRIVE and notice how electric vehicles have now become a trend, and miniaturised and compact automobiles inhabit the roads. These vehicles are lighter, hence, less energy is used, making them more environmentally friendly.

Metals like steel have been commonly used to manufacture vehicles, but today, strategies to reduce weight through material selection, structure and system design[1] are a common practice. Lighter materials such as aluminium and composite are now preferred.

Weight is the most significant factor contributing to the fuel economy and to carbon dioxide emission. Table 1 breaks down the weight of a vehicle  (adopted from Lutsey, 2010 and Stodolsky et al., 1995). When looked at individually, we can pinpoint components that have a high potential to go lighter in a bid to reduce the overall weight of a vehicle.

Among all the systems, the body is the most important, carrying a quarter of the weight of a vehicle. Most recent research and development (R&D) focuses on the system's weight over time, and the opportunity to introduce increased weight reduction comes from using advanced lightweight materials and new strategies.

The other two cardinal systems are the powertrain (an assembly of every component that pushes the vehicle forward) and the chassis (the skeleton of the vehicle). They carry approximately 20 to 25 percent of the weight of a vehicle.

Just using an advanced material for the running gear in the powertrain system can slough six percent off its weight. Replacing more parts with lightweight materials in the powertrain and chassis can further reduce the gross vehicle weight by one to two percent.

However, there are challenges in achieving lightweight manufacturing.

One is in the process of making changes, such as the material and design alterations. For example, welding aluminium to steel can happen relatively fast, but the process consumes more energy and requires skilled workers.

Another challenge is cost. Aluminium is significantly more expensive compared to steel.  In terms of performance, most lightweight materials perform better or are on par with their former counterpart. However, lighter materials may make safety a main concern. In cutting weight, the manufacturer may end up creating an unsafe vehicle.

The question now is, how do you change the structural composition of something so sturdily solid and not make a mess out of it? How do you maintain safety?

This is when tailor blank technology, an advanced manufacturing method to produce semi-finished sheet products with different thicknesses and types of material, comes into play. With this technology, weight can be reduced tremendously via a combination of different materials and thicknesses. It maintains structural integrity and, at the same time, reduces weight.

There are four ways to go about it. Tailor welded blanks (TWB) join materials of different grades, thicknesses or coatings through a welding process; patchwork blanks reinforce blanks by adding another blank on top of the base metal; tailor-rolled blanks (TRB) introduce continuous variation to the sheet thickness; and tailor heat treated blanks (THTB) alter material properties through local heat treatment (Figure 1).

Research at the Metal Forming Laboratory, School of Mechanical Engineering, USM

The Metal Forming Research Laboratory was established in 2006 for research into precision metal forming. Today, many of its main projects are focused on lightweight manufacturing.

Hybrid manufacturing is conducted there, using a hybrid machine that combines two or more processes. The project is funded under the Prototyping Research Grant Scheme from the Ministry of Higher Education.

We then deal with tailor blank technology that applies TWB using laser welding and friction-stir welding, and TRB using a forging process. These projects are funded under the Fundamental Research Grant Scheme from the Ministry of Higher Education and the Research University Grant from Universiti Sains Malaysia.

Set for Industrial Revolution 4.0 (IR4.0), we also have additive manufacturing, one of the pillars aiming for quick and reliable product development. At the laboratory, wire arc additive manufacturing techniques are used on deposited metal parts with the help of a 3D welding machine customised especially for research purposes.

With all these methods at our disposal, it is certainly an exciting time at The Metal Forming Lab at USM. We are seeking partners and collaborators from the industry and academia to further develop the technology. For further information, please visit our website at http://metalforming.eng.usm.my.

Footnote:

[1] https://gesrepair.com/what-are-the-benefits-and-challenges-of-lightweight-manufacturing/

References
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Assoc. Ir. Dr. Ahmad Baharuddin bin Abdullah

is Associate Professor of Mechanical Engineering at the School of Mechanical Engineering in Universiti Sains Malaysia.


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