Sliding rod model

Various models are available [20] to describe semiflexible chains. Some are based on expansions either close to the gaussian coil or to the rigid rod limits, while others interpolate between these two chain stiffness limits. One of these, the sliding rod model [19], is described here because of its inherent simplicity. 

Modeling of curves and surfaces has widened the capability of kinematic modeling. Joints can be defined for movements along and around a curve (Figure 5-21). The rod can slide along the curve, roll on the curve, and rotate around the curve according to the degrees of freedom allowed for the movements. A point-curve type joint also can be defined. 

As a model for work with partial energy dissipation, consider the gas-filled cyUnder-and-piston device depicted in Fig. 3.18. This device has an obvious source of internal friction in the form of a rod sliding through a bushing. The system consists of the contents of the cylinder to the left of the piston, including the gas, the rod, and the bushing the piston and cylinder wall are in the surroundings. 

Consider the model shown in Fig. 4.20 which is similar to Fig. 4.19. Here, a rod of length I with mass m and moment of inertia I is pivoted at point O at one end and slides against a moving surface at another. Initially, the rod makes an angle 0q with... 

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