The piston in an engine is attached to a connecting rod AB, which in turn is connected to a crank arm BC (see figure). The piston slides without friction in a cylinder and is subjected to a force P (assumed to be constant) while moving to the right in the figure. The connecting rod, which has diameter d and length L, is attached at both ends by pins. The crank arm rotates about the axle at C with the pin at B moving in a circle of radius R. The axle at C, which is supported by bearings, exerts a resisting moment M against the crank arm.
(a) Obtain a formula for the maximum permissible force Pallow based upon an allowable compressive stress σc in the connecting rod.
(b) Calculate the force Pallow for the following data: σc = 160 MPa, d = 9.00 mm, and R = 0.28L.

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Cylinder Piston Connecting rod