FEM, FEA, Frame, Moment, Shear, find Stiffness Matrixx

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SUMMARY

The discussion centers on the challenges of obtaining the stiffness matrix for a frame structure using hand calculations versus software like CSI SAP2000. The user expresses skepticism about the feasibility of manual calculations due to shear and axial deformation complexities. A response clarifies that while it is possible to create the stiffness matrix by hand, attention must be paid to the pinned connections at the joints, which affect the matrix's formulation. The response emphasizes that creating the stiffness matrix is just one part of the overall frame analysis process.

PREREQUISITES
  • Understanding of stiffness matrix formulation in structural analysis
  • Familiarity with frame structures and their behavior under loads
  • Knowledge of pinned connections and their impact on structural calculations
  • Proficiency in using CSI SAP2000 for structural analysis
NEXT STEPS
  • Study the derivation of stiffness matrices for frame structures
  • Learn about the effects of shear and axial deformation in structural analysis
  • Explore methods for analyzing pinned connections in frame structures
  • Investigate advanced features of CSI SAP2000 for frame analysis
USEFUL FOR

Civil engineers, structural analysts, and students studying frame analysis who seek to deepen their understanding of stiffness matrix calculations and software applications in structural engineering.

McLovinn
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Homework Statement


Hi,

I need some help analysing this frame. First of all i bellive its hard, if not impossible, to get as detailed results by hand calculations as my softwear CSI Sap2000. Becourse of shear and axial deformation.

Is it possible to obtain the stiffness matrix of this frame at all, or do i need to look at different methods.

Can you pleas tell me where to ask if this is wrong forum?

Thanks, most sincerly!

Homework Equations


http://www.sut.ac.th/engineering/civil/courseonline/430332/pdf/07_matrix_frame.pdf

The Attempt at a Solution



Not even sure if its possible.
 

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McLovinn said:

Homework Statement


Hi,

I need some help analysing this frame. First of all i bellive its hard, if not impossible, to get as detailed results by hand calculations as my softwear CSI Sap2000. Becourse of shear and axial deformation.

Is it possible to obtain the stiffness matrix of this frame at all, or do i need to look at different methods.

Can you pleas tell me where to ask if this is wrong forum?

Thanks, most sincerly!

Homework Equations


http://www.sut.ac.th/engineering/civil/courseonline/430332/pdf/07_matrix_frame.pdf

The Attempt at a Solution



Not even sure if its possible.

You shouldn't have a problem creating the stiffness matrix for your frame by hand, if that's really what you want to do. Even for such a small frame, it's going to be pretty tedious.

I think one problem you might have with creating the stiffness matrix is what to do about the joints which connect the red parts of the frame to the blue parts. These four joints appear to be pinned connections. As such, each joint will only support forces; no moments can be transmitted, therefore, you must modify your stiffness matrix to reflect this situation.

Good Luck! :smile:

Of course, creating the stiffness matrix is only one step in analyzing this frame.
 

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