In the suspension design, the relationship between force and deformation, that is, the relationship between the vertical external force on the wheel and the displacement of the wheel center relative to the body is usually called the elastic characteristic curve of the suspension. The slope of the curve is the rigidity of the suspension.A. Linear elastic propertiesLinear elastic properties, that is, suspension deformation changes in proportion to the load. Its stiffness G is constant. This is the general leaf spring suspension.Cars have linear elastic properties, and the natural frequency of the car ’s vibration will change with the amount of load during use, especially for large trucks and buses after the suspension load changes. This results in severe bumping (longitudinal angular vibration) of the vehicle body, which makes the vehicle comfortable to drive.