Frame Analysis Using Method of Members, 3Hinged Arch Help

[iceicebaby03]

1. Determine the type and magnitude of force in bars BD and BE using method of members.
2. Well, I don't know where to start. I know there are three equations EFy=0, EFx=0, EMc=0 but I don't know what the first member to consider and how to solve this type of problem.
3. There is a hint that first isolate each truss as a free body. No final answer is given in the textbook.
So far I isolated each truss, then sum the moments at A for the left truss then moments at C for the right truss. Am I on the right path?

I need your help. Please help.! Thanks!

 

[nvn]

iceicebaby03: Yes, you are on the right path. Hint: Don't you also want to use your other two relevant equations in item 2 of post 1, on each of your two isolated trusses?

 

[Mene]

1. To determine the forces in bars BD and BE, we can use the method of members. This method involves isolating individual members and analyzing the forces acting on them. We can start by considering the entire 3-hinged arch as a free body and applying the equations of equilibrium (EFx=0, EFy=0, EMc=0). This will give us three equations and three unknowns (forces at points B, D, and E). Then, we can isolate each truss as a free body and use the same equations of equilibrium to solve for the remaining unknown forces. By solving these equations simultaneously, we can determine the type (compression or tension) and magnitude of the forces in bars BD and BE.

2. It seems like you are on the right track. The first step is to identify all the unknown forces and then use the equations of equilibrium to solve for them. It is important to consider the entire structure as a free body, as well as individual trusses, to ensure that all forces are accounted for. Make sure to label all the forces and directions correctly to avoid any mistakes in your calculations.

3. It is good that you are using the method of members to solve this problem. Remember to also consider the reactions at the supports (A and C) when using the equations of equilibrium. Once you have solved for all the unknown forces, you can check your answer by ensuring that the sum of forces and moments at each joint is equal to zero. If you are still having trouble, you can consult your textbook or reach out to a professor or tutor for further assistance. Good luck!