HARSHNESS in the ride of an automobile is felt as a disagreeable tremor or shock, sudden in nature as distinguished from the opposite sensation which could be described as slow, soft, and mellow, the authors state. They add that it is in the nature of a tremor having a frequency in the higher shake range and approaching the threshold of audibility.
This paper is limited to analysis of the harsh vibrations which emanate from tire contact with the road, excluding the effects of the tires themselves.
The authors describe methods of measuring harshness both in the laboratory and on the road, discuss car harshness in its relation to rigidity, and touch upon its relation to suspension.
It is pointed out that there has been a decided trend toward more rigid construction and that, in general, harshness has increased as rigidity has been obtained. It is also noted that fore-and-aft shocks are more pronounced with independent suspension than when leaf springs are used.
Two methods of reducing harshness are explained, although the authors state that there are probably many ways of solving the problem.