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The image below is of the simplified suspension geometry. The following table describes the sequence of joints. You should be able to infer what the lines in the sketch represent based on which joints they attach to. There a lot of parts between the tyre contact patch and the upright, but we don’t need to concern ourselves with them just now.
Code | Type of Joint | Description |
|---|---|---|
SB1 | Spherical Bearing | Connects the Upright to the Lower Control Arm (LCA) |
SB2 | Spherical Bearing | Connects the Pushrod Upright to the LCAUpper Control Arm (UCA) |
SB3 | Spherical Bearing | Connects the Upright LCA to the Upper Control Arm (UCA)Pushrod |
SB4 | Spherical Bearing | Connects the Pushrod to the rocker (don’t worry about this is) |
SB5 | Spherical Bearing | Connects the UCA to the Chassis |
SB6 | Spherical Bearing | Connects the UCA to the Chassis |
Cl1 | Clevis | Connects the LCA to the Chassis |
CL2 | Clevis | Connects the LCA to the Chassis |
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Your task is to find the forces (X,Y,Z) at CL1 and CL2. You can break this into two parts:
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This is the start of the LCA, and you want to translate the forces from the contact patch to here. You’ll need to consider the reaction forces at SB1 and SB3SB2. Some notes:
The UCA cannot apply any force in Y (No reaction force in Y from SB3)is connected to spherical bearings on the chassis. What does this say about its ability to exert force onto the upright in the Y direction?
Do not consider moments about Y. These are taken care of by steering, which is not included in this project
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You’ll need to consider the forces you calculated at SB1, as well as reaction forces from SB2SB3, CL1, and CL2. Some notes:
This is a statically indeterminate problem. What assumptions can be made for a “worst-case” loading condition on CL1 and CL2?
The pushrod has a spherical bearing on both ends. What does this imply about the force it exerts on the LCA at SB3?
You can use the CAD to find the dimensions you need, or refer to the images below.
Image View 1: Side view in Y-Z planes, Z+ to the right X+ into the page
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Image View 2: Front View in Y-X plane, X+ to the right, Z+ out of the page
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View 3: Top view in X-Z plane, X+ to the right, Z+ up, and Y+ out of the page
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