Thin-walled rods with semi-open profile for semi-solid automotive suspension

A new type of thin-walled rods with a semi-open cross-section is suggested and the optimization performed. Descriptive of this class of thin-walled beam-like structures is the closed but flattened profile. In this work, an intermediate class of thin-walled beam cross sections is studied. The cross-section of the beam is closed, but the shape of the cross-section is elongated and curved. The walls that form the cross section are nearly equidistant. The principle application of the theory of semi-open thin-walled beams is the twist beam of the semi-solid trail arm axle. The analytical expressions for the effective torsion stiffness and effective bending stiffness of the twist beam are derived in terms of section properties of the twist beam with a semi-open cross section. Based on the stiffness coefficients of the twist beam, the roll rate, chamber and lateral rigidity of the suspension are derived.