The figure shown below (Fig. 1) is a schematic representation of a conversion system linear-rotational motion. The system consists of a piston with one degree of freedom of movement (vertical displacement) connected to a connecting rod-crank. The necessary vertical force to be applied on the piston in order to convert the vertical displacement into shaft rotation varies according to the piston position. The figure shows only one instant of the system in which the vertical force applied is equal to 35 KN. Considering this instant as static (that is, imagine that the axis is applying a moment of such magnitude that it counteracts the displacement of the piston) solve the following subsections. Fig. 2 shows the actual geometry of the connecting rod (element ab) of the schematic system. a) Calculate what should be the minimum thickness ? of the connecting rod (element ab) if to guarantee its structural safety the stress must not exceed a value of 160 MPa at any of its points. Consider the section A-A shown in Fig. 2 as the section with the smallest cross-sectional dimension. b) Once you have calculated the minimum thickness of the connecting rod, calculate the stress that will be developed in section B-B (see Fig. 2). A hollow bolt is used to hold the piston and connecting rod offsets together as shown. in Fig.3. c) If the outside diameter of the bolt is 25 mm, what should its thickness be if the shear stress in this element must not exceed 125 MPa.
The figure shown below (Fig. 1) is a schematic representation of a conversion system linear-rotational motion. The system consists of a piston with one degree of freedom of movement (vertical displacement) connected to a connecting rod-crank. The necessary vertical force to be applied on the piston in order to convert the vertical displacement into shaft rotation varies according to the piston position. The figure shows only one instant of the system in which the vertical force applied is equal to 35 KN. Considering this instant as static (that is, imagine that the axis is applying a moment of such magnitude that it counteracts the displacement of the piston) solve the following subsections. Fig. 2 shows the actual geometry of the connecting rod (element ab) of the schematic system.
a) Calculate what should be the minimum thickness ? of the connecting rod (element ab) if to guarantee its structural safety the stress must not exceed a value of 160 MPa at any of its points. Consider the section A-A shown in Fig. 2 as the section with the smallest cross-sectional dimension.
b) Once you have calculated the minimum thickness of the connecting rod, calculate the stress that will be developed in section B-B (see Fig. 2).
A hollow bolt is used to hold the piston and connecting rod offsets together as shown. in Fig.3.
c) If the outside diameter of the bolt is 25 mm, what should its thickness be if the shear stress in this element must not exceed 125 MPa.
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