Osama, Muhammad

Improving Damping of Automotive Suspension - 76p. ; Soft Copy 30cm.

Most heavy-duty automotive suspensions use high-strength helical steel
springs, which have linear elastic behavior but very little intrinsic material
damping. So, auxiliary hydraulic dampers are the only things that keep the
vehicle stable and comfortable to ride in. In very rough off-road conditions,
these fluid-based dampers are very likely to break down or lose their
effectiveness due to heat, which makes armored SUVs and other strategic
logistics and defense platforms very vulnerable. This study presents a new
polymer-metal composite (PMC) spring topology that is meant to provide
built-in passive damping and fail-safe mechanical redundancy. To do this, a
high-strength SAE 9254 steel coil spring was completely covered in a
thermoset neoprene (chloroprene rubber) shell. A custom compression
molding workflow was created to make sure that the adhesion between the
two surfaces was strong and that there was no delamination. We used a servo
hydraulic universal testing machine (UTM) to test dynamic performance
under cyclic loading conditions. We then added the resulting coefficients to a
quarter car model on Simulink as well as 7-degree-of-freedom (7-dof) full-car
vehicle dynamics model on MATLAB. Tests in the real-world show that
composite architecture causes strong non-linear viscoelasticity. Transient
oscillations die down quickly, according to time-domain analysis. This means
that the suspension settles down much faster after a shock event. These results
show that composite springs wrapped in neoprene are a theoretically long
lasting, fail-safe building solution that improves dynamic stability and
completely protects the structural steel core from corrosion-related fatigue.


MS Design and Manufacturing Engineering

670