Force in each member of truss

[spacecataz]

Homework Statement

Determine the force in each member of the truss shown.

Homework Equations

$$\Sigma$$Fx = 0
$$\Sigma$$Fy = 0
$$\Sigma$$M = 0

The Attempt at a Solution

I divided up the truss into different systems, the whole truss, and then a system for each pin. I must be doing something wrong because I found that FAP = 0 and FA = 0

As far as the free body diagram, I wasn't sure about the force on the rollers, I just had a single horizontal force pointing inward for each and a force in the x and y directions for the pin at point B. Can someone give some direction?
Thanks

 

[anathema]

Hello,

It's great that you are trying to solve this problem! Let me give you some tips to help you find the correct solution.

First, when dividing the truss into different systems, it's important to make sure that all the forces acting on each system are accounted for. This includes the external forces (such as the applied load) and the internal forces (the forces within the truss members).

Second, when solving for the forces in each member, it's important to remember that the truss is in static equilibrium, meaning that the sum of all the forces acting on it must equal zero (as you have correctly stated in your equations). This includes both the horizontal and vertical forces, as well as the moments.

Third, when drawing the free body diagram, it's important to include all the forces acting on each pin (including the forces acting on the rollers). This will help you determine the correct equations to solve for the forces in each member.

Lastly, I would recommend breaking down the truss into smaller sections (such as AB, BC, CD) and solving for the forces in each section separately. This will make the problem more manageable and easier to solve.

I hope these tips help guide you in the right direction. Keep practicing and don't be afraid to ask for help if you get stuck. Good luck!

 

[Moetasim]

I would approach this problem by first reviewing the fundamental principles of statics and structures. This would include understanding the basic concepts of forces, moments, equilibrium, and the method of joints for analyzing truss structures.

Next, I would carefully examine the given truss and identify all the external and internal forces acting on each member. This would involve creating a detailed free body diagram for each joint, considering the forces acting on each joint, and using the equations of equilibrium (\SigmaFx = 0, \SigmaFy = 0, \SigmaM = 0) to determine the unknown forces.

I would also consider the assumptions made in analyzing truss structures, such as the members being idealized as weightless and the joints being pinned or fixed. These assumptions may affect the accuracy of the results and should be acknowledged.

Once all the external and internal forces have been determined, I would then check for stability and ensure that the truss is in equilibrium. If there are any discrepancies or inconsistencies, I would review my calculations and assumptions to find any errors.

In conclusion, analyzing the forces in a truss structure requires a thorough understanding of statics and structures principles and careful consideration of all external and internal forces. It is important to follow a systematic approach and check for accuracy and stability in the final results.