Complex frames - analytical calculations

In summary, the author is asking for advice on how to solve frames that are not hinged and are subject to bending.
  • #1
FEAnalyst
342
144
TL;DR Summary
How can one solve complex frames, like those shown in the post?
Hi,

I came across some interesting frames recently. Here they are:

ramy.JPG

I wonder if all these frames can be solved analytically. If yes then how to do it ? Examples a) and d) are planar frames with diagonal members while b) and c) are spatial frames: b is subjected to uniformly distributed load while c) is subjected to remote loads (forces acting at a distance ##r## and transmitted to the frame via rigid links). How can I solve these examples ? I guess that at least some of them are statically indeterminate. Should I break them into individual beams and solve their members separately ? Is there a book or online source where I could find similar cases ?

Thanks in advance for your help
 
Engineering news on Phys.org
  • #2
Where you show dots, are those pin (revolute) joints, welds, or what?
 
  • #3
I should have drawn them better. All of these are not hinges but rigid connections of the beams.
 
  • #4
I think there is a difficulty here because the joints are not hinged, so the members are subject to bending. As a result, the elasticity of the members will affect the result. For instance, in (d), the lateral load on the top support will depend on the rigidity of the bottom support and vertical member in bending.
 
  • #5
I should have mentioned what these frames actually represent:
a - workshop crane
b - curtain rod
c - support of a seat in a bus
d - different type of crane
 
  • #6
I have solved similar systems analytically,, but it is a whole lot of work. I would think and FEAnalyst would simple to a finite element model.
 
  • #7
Sure, it’s very easy to solve these models with FEA (even using some free online apps) and I already did that. But I would also like to learn how to do it analytically. Since these are statically indeterminate systems, it seems that, apart from FEM, only flexibility or stiffness method can be used to solve them.
 
  • Like
Likes Mech_LS24

1. What are complex frames?

Complex frames are structural systems composed of interconnected beams, columns, and other elements that form a three-dimensional framework. They are commonly used in building construction to support loads and resist forces such as gravity, wind, and seismic activity.

2. How are analytical calculations used in complex frames?

Analytical calculations are used in complex frames to determine the internal forces and stresses within the various members of the frame. These calculations involve applying principles of mechanics and mathematics to solve for reactions, bending moments, shear forces, and other parameters that are critical for designing and analyzing the frame.

3. What factors are considered in analytical calculations for complex frames?

Several factors are considered in analytical calculations for complex frames, including the geometry of the frame, the types of loads it will be subjected to, the material properties of the members, and the boundary conditions at the supports. These factors can significantly affect the internal forces and stresses within the frame and must be carefully considered in the calculations.

4. Are there any limitations to using analytical calculations for complex frames?

While analytical calculations are a powerful tool for analyzing complex frames, they do have some limitations. For example, these calculations assume that the frame is perfectly rigid, which may not be the case in real-world scenarios. Additionally, they may not account for certain factors such as non-linear behavior or material failure, which may require more advanced analysis techniques.

5. How do analytical calculations benefit the design of complex frames?

Analytical calculations play a crucial role in the design of complex frames by providing engineers with valuable information about the internal forces and stresses within the frame. This information can help determine the most efficient and cost-effective design, identify potential problem areas, and ensure that the frame can safely support the intended loads. It also allows for the optimization of material usage and can aid in meeting design codes and standards.

Similar threads

  • Mechanical Engineering
Replies
8
Views
1K
Replies
33
Views
3K
  • Mechanical Engineering
Replies
2
Views
853
  • Mechanical Engineering
Replies
6
Views
3K
  • Mechanical Engineering
Replies
6
Views
2K
  • Classical Physics
Replies
3
Views
772
Replies
4
Views
1K
  • Mechanical Engineering
Replies
2
Views
896
  • Mechanical Engineering
Replies
6
Views
4K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
866
Back
Top