Page 334 - Cam Design Handbook

THB11 9/19/03 7:33 PM Page 322

322 CAM DESIGN HANDBOOK

M
x s

M eq K s
x s
m
K eq

(a) Equivalent system. (b) Infinite tire stiffness.

M
M
x s
x s
m

K s
K s

K t
K t

(c) Zero tire mass. (d ) Independent lumped parameters.
FIGURE 11.3. Reductions of the suspension model.

K
.
w = s = 649 rad s =103 Hz.
.
n
M
Approach 2: Assume Zero Tire Mass. Assume that the tire has no mass so
that the system takes the form of Fig. 11.3c. Neither the tire mass nor its degree
of freedom are necessary for modeling, but the tire stiffness does influence the
system through an equivalent stiffness of the springs in series (discussed in
Section 11.4.3.2) defined by