The Body Structure and Ergonomic Design of Electric Vehicles and Human Powered Vehicles: Engineering Practice from Lightness to Comfort

Keywords: electric vehicle, rickshaw, body structure, lightweight, ergonomics NVH

abstract

The structure of the vehicle directly affects its performance and user experience. This article analyzes the technical path and engineering cases from material selection, structural optimization to NVH control.

3.1 Comparison of Main Framework Materials

High strength steel (HSS):

Yield strength of 420MPa, density of 7.8g/cm 3, cost of $1.2/kg, suitable for mid to low end vehicle models (such as Thai Tuk Tuk modified models).

Aluminum alloy 6061-T6:

Yield strength of 275MPa, density of 2.7g/cm 3, weight reduction of 30%, but cost increase of 50% (such as the Indian Bajaj RE60 model).

Carbon fiber composite materials:

The tensile strength is 5000MPa, the density is 1.8g/cm 3, and the weight is reduced by 50%, but the cost is as high as $30/kg (only used for high-end customized models).

3.2 Structural optimization techniques

Topology optimization:

Define load conditions in Altair OptiStruct (such as a full load of 1000N) and generate optimal material distribution (such as a hollow design in the middle of the frame, reducing weight by 15%).

3D printing connectors:

Using EOS M290 printer (SLM process), titanium alloy joints (tensile strength 900MPa) are manufactured, with a 40% increase in load-bearing capacity.

3.3 Ergonomic Design

Seat layout:

According to SAE J1100 standard, the driver's seat height is 650-700mm, and the backrest angle is 15 ° -20 ° to reduce lumbar fatigue (such as Vietnam VinFast electric rickshaw).

Pedal position:

Adjustable range 300-400mm (front rear), suitable for users with a height of 1.5-1.8m, pedal force<50N (compliant with ISO 2631-1 vibration standard).

3.4 NVH Control Strategy

Motor noise suppression:

Using sine wave drive (THD<5%), combined with sound-absorbing cotton (thickness 10mm), reduces electromagnetic noise by 8dB (such as the Indian Ather 450X model).

Wind noise optimization:

Optimize the vehicle body streamline through CFD simulation (drag coefficient<0.35), and ensure that the interior noise during high-speed driving is less than 70dB (weighted by A).

3.5 Durability testing

Road simulation test:

Simulate 100000 kilometers of road conditions on the MTS 810 vibration table (frequency 5-50Hz, amplitude ± 5mm), with no cracks in key areas (such as the Indian Kinetic Green model).

Salt spray corrosion test:

According to ASTM B117 standard, conduct a 1000 hour neutral salt spray test, and the corrosion area of the frame is less than 5% (applicable to coastal city operations).

conclusion

Aluminum alloy and high-strength steel are mainstream materials that require topology optimization and ergonomic design to balance lightweight, comfort, and durability.