1. Analysis Solved by Replacing Units with Lumped Masses

The deflection of a vehicle frame is a critical factor in structural analysis, measuring how much the frame deforms under external loads. This directly affects the structural integrity and driving stability of the vehicle.

Vehicle body frame deflection caused by the weight of vehicle component units can occur when the vehicle's designed load limit is exceeded. 'Unit weight' refers to the weight of the major components constituting the vehicle, and this weight constitutes the load applied to the vehicle body frame. If this load is excessively large or improperly distributed, the vehicle body frame may deflect.

Vehicle Component Units

2. What Is the Correct Design Approach to Prevent Vehicle Body Frame Deflection Based on the Selection of Support Locations?

Regarding the causes of vehicle frame deflection:

First, the vehicle body frame is designed to accommodate specific loads. There can be many contributors to those specific loads, but the most fundamental is the weight of the various relative parts — i.e., units — supported by the frame. If the unit weight exceeds this limit, or if heavier-than-expected components are installed, excessive pressure is applied to the frame, which can cause deflection.

Second, if the holders (fixtures) used to move and transport the vehicle body frame during the manufacturing process are arranged asymmetrically, excessive loads become concentrated, potentially causing frame deflection at those locations. Examples include cases where the supports that fix the frame during transport are designed to be offset to one side, or where excessive loads are applied depending on the arrangement pattern, number, or type of supports.

Third, when replacing or upgrading vehicle component units with heavier or larger ones, deflection may occur if the original frame was not designed to withstand the additional weight.

Therefore, experiments and CAE analyses are conducted with the objective of deriving optimal methods and design solutions to prevent vehicle body frame deflection under these various circumstances.

Vehicle Body Frame Structure

Analysis Program : midas NFX

Analysis Type : Linear Static Analysis

Analysis Purpose : 
- Structural safety review by isolating and modeling only the target component (Motor Shaft) from a complex structure
- The loads, boundary conditions, forces, and positions of the independent analysis target are redefined as substitutes (Results : displacement, stress)

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