Calculating Forces in a Concrete Slab Supported by a Chain

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A 500-kg concrete slab is supported by a chain and sling from a front-end loader, with one mechanism supporting half the weight. The force in cylinder CD was initially calculated incorrectly, with the correct value being 7680 N in compression. The discussion emphasizes the importance of creating free body diagrams (FBDs) to analyze the forces accurately rather than simply dividing the weight. Participants noted the necessity of considering all forces acting on the system, including those from the pins and the bucket. The conversation concluded with an acknowledgment of the initial error in calculations and the value of collaborative problem-solving.
OmniNewton
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Homework Statement


A 500-kg concrete slab is supported by a chain and sling attached to the bucket of the front-end loader shown. The action of the bucket is controlled by two identical mechanisms, only one of which is shown. Knowing that the mechanism shown supports half of the 500-kg slab, determine the force
(a) In cylinder CD,
(b) In cylinder FH.
EQ4HPbq.png

Homework Equations

The Attempt at a Solution


Using the summation of Fy

FDCsin26 - 2452.5 = 0
FDC = 5594.5
The correct answer for FDC is 7680 N compression
 
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OmniNewton said:

Homework Statement


A 500-kg concrete slab is supported by a chain and sling attached to the bucket of the front-end loader shown. The action of the bucket is controlled by two identical mechanisms, only one of which is shown. Knowing that the mechanism shown supports half of the 500-kg slab, determine the force
(a) In cylinder CD,
(b) In cylinder FH.
EQ4HPbq.png

Homework Equations

The Attempt at a Solution


Using the summation of Fy

FDCsin26 - 2452.5 = 0
FDC = 5594.5
The correct answer for FDC is 7680 N compression

This is a complicated mechanism. You can't just split the weight in two and say that's the force on Pin D.

You've got to start making FBDs at the bucket and work your way back until you reach the pins connecting the cylinders to the arm.
 
Is it not possible to dismantle the bucket leaving the 2 two force members and the weight of the slab. Now one knows the external forces of the bucket and can now calculate. Therefore the only forces in the y-direction are the weight of the slab and the component of FDC.
 
OmniNewton said:
Is it not possible to dismantle the bucket leaving the 2 two force members and the weight of the slab. Now one knows the external forces of the bucket and can now calculate. Therefore the only forces in the y-direction are the weight of the slab and the component of FDC.
Not so. You can quickly deduce the tension in AB, for example.
 
haruspex said:
Not so. You can quickly deduce the tension in AB, for example.
It would seem I am missing a force coming from Pin D. Sorry guys! Thanks for your help I determined my error!
 

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