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This study provides a numerical evaluation of the dynamic coupling that exists between the powertrain, suspensions, and tire dynamics in class 8 trucks. The spatial dynamics of the driveline, including the offset angels that commonly exist in practice, are modeled along with a lumped-parameter representation of the suspension and tire dynamics in vertical, longitudinal, and torsional directions. The model is used to show how the suspension dynamics and the angle change that it causes in driveline geometry can affect the vibrations resulting from the powertrain. The numerical model is also used for a parametric study in which the effect of various suspension and powertrain parameters on the dynamic coupling that exists between the two is evaluated.

This experimental study determines the effect of truck frame stiffness on truck ride, as measured by B-post vertical and fore-aft accelerations. After describing the test setup, the paper will describe the details of two truck frames that are used in a series of tests conducted on a class-8 truck in the laboratory. The frames that are used for the tests include what commonly is used in production trucks in North American markets (called “baseline” frame), and a frame that is 15% thinner (called “thin” frame). The test results, which are analyzed in frequency domain, are compared for the two frames. They indicate that the thin frame performs similar to the baseline frame when the truck is subjected to heave inputs. For roll inputs, the thin frame causes an increase in B-post accelerations, mostly at frequencies associated with the frame beaming and the primary (axle) suspension resonance.

This study provides an experimental account of the effect of panhard rod suspensions on heavy truck ride, as evaluated by the B-post vertical and fore-aft accelerations. After describing the test setup, the paper will describe the details of two rear cab suspensions that are commonly used in North American trucks. Cab suspensions with dampers or similar elements that are used to provide lateral forces at the rear of the cab (called “baseline” cab suspension for the purpose of this study) and those that use a lateral link with a torsion spring at one end-commonly called “panhard rod”-are the two classes of rear cab suspensions that are considered in this study. The tests are performed on a class 8 truck that is setup in the laboratory for the purpose of providing good test repeatability and conducting an accurate design of experiment. The test results, which are analyzed in frequency domain, are compared for the two cab suspensions.