Engineers seeking to significantly improve the efficiency and performance of electric motors could benefit from using aluminum matrix composites (AMCs), according to research from the Innovate UK ‘Make it Lighter with Less’ R&D competition.
Metal Matrix Composites are metallic materials that have been reinforced with a secondary high-performance material. The format of the secondary material is typically a long-fiber, short fiber or particulate.
The project, led by AMC specialist, Alvant, in collaboration with GE Aviation, YASA Motors and the National Composites Center, achieved a 40% rotor weight saving on an axial flux electric motor while increasing the rotor’s power-to-inertia ratio potential. In addition, the number of assembly line parts was reduced which can result in a shorter assembly time.
Alvant achieved a 40% rotor weight saving on an axial flux electric motor (pictured, patent pending) while increasing the rotor’s power-to-inertia ratio potential.
As electrification increases, vehicle manufacturers are seeking to optimize motor efficiency maps—for example, by improving the efficiency as a function of torque and speed that ultimately determines the energy consumption for vehicles. The industry faces the challenge of identifying ways to improve efficiency and performance, while simplifying manufacturing and overall cost.
Alvant’s proprietary AMCs enable components to be optimized for strength-to-weight and stiffness-to-weight ratio precisely where they are needed, even within a single continuous product.
Alvant’s proprietary Advanced Liquid Pressure Forming (ALPF) method can selectively reinforce areas of a component with one of its performance materials in a near net shape manufacturing approach. Alternatively, Alvant’s materials can be applied as discrete inserts into a component allowing for cost efficiency where an array of similar inserts are the solution.
By adopting AMCs in rotor design, Alvant was able to realize further benefits. In an axial flux electric motor application, Alvant’s technology can not only save weight; the component’s lower mass and reduction in force means engineers may be able to eliminate the number of fixing bolts required, reducing the bill of materials and assembly time.
Using AMCs, we have been able to attack the weight yet retain the stiffness of the electric rotor, to minimize parasitic mass, improving the power-to-inertia ratio and therefore efficiency and responsiveness. In addition, we can also offer better thermal resistance, up to 300 °C, making AMCs a more suitable material than polymer composites for applications such as motors, batteries, energy recovery systems, fans and flywheels.—Richard Thompson, commercial director of Alvant
In addition to the manufacturing and in-service gains, Alvant’s AMC is more sustainable, thanks to the ability to separate the fibers from the aluminum at the end-of-life stage.
Designers must increasingly factor ‘whole life cost’ into design and it’s an area where AMCs score well.—Richard Thompson
While the Innovate UK/YASA project focused on a passenger car rotor, Alvant’s own research programs demonstrate the gains to be made by adopting AMCs across multiple high stress or high temperature applications in sectors such as aerospace, automotive, defence, consumer goods and sporting equipment.
Established as CMT originally in 2003, Alvant’s goal has been the exploration of the potential of Liquid Pressure Forming (LPF) as a process for manufacturing AMCs. This has resulted in the creation of a more sophisticated process known as Advanced Liquid Pressure Forming (ALPF). ALPF is the method by which Alvant brings together aluminum, which acts as the matrix, and a high strength reinforcement fiber to create a high-performance aluminum Matrix Composite material.