Securing a 3D Frame: How to Analyze and Solve for Loads?

  • Context: Graduate 
  • Thread starter Thread starter epheterson
  • Start date Start date
  • Tags Tags
    Frame
Click For Summary

Discussion Overview

The discussion revolves around analyzing and solving for loads in a 3D frame that is subjected to forces in multiple directions. Participants explore the transition from 2D to 3D analysis, particularly focusing on the implications of statically indeterminate systems and the need for accurate moment equations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant expresses difficulty in transitioning from 2D to 3D analysis, noting the complexity introduced by the third dimension and the potential for a statically indeterminate system.
  • The participant mentions having created vectors and initial equations but struggles to find a valid solution, particularly for lateral loads.
  • Another participant suggests that the problem may be straightforward but acknowledges their own lack of recent experience with statics.
  • A later reply indicates that the original poster resolved their issue by adding the third direction to their moment equation, implying a solution was found without further input from others.
  • There are expressions of frustration regarding the lack of responses and perceived unhelpfulness of earlier comments, highlighting a sense of urgency for numerical solutions.

Areas of Agreement / Disagreement

The discussion reflects a lack of consensus, with some participants feeling that the problem is simple while others express confusion. The original poster ultimately claims to have resolved their issue independently.

Contextual Notes

Participants reference specific vectors and equations but do not provide detailed mathematical steps or assumptions, leaving some aspects of the analysis unresolved.

Who May Find This Useful

This discussion may be of interest to individuals working on structural analysis, particularly those transitioning from 2D to 3D frameworks in engineering contexts.

epheterson
Messages
22
Reaction score
0
Hey all,
I'm working on an experiment and we have a frame which will be exposed to loads in all directions. I'm trying to analyze how to best secure it and am having trouble considering the 3D analysis, while the 2D analysis seems rather simple to me. I was informed the 2D analysis is insufficient, though, and must consider 3D. I believe when I enter the 3rd dimension I introduce a statically indeterminate system.
I've attached my FBD's and initial 2D equations, could you please guide me in making these 3D. The lateral 2G load especially needs to be considered in 3D. I've created the vectors necessary, but can't find a valid solution. My moment equation was about the CG and included only these two cables, when I tried to solve with my TI-89 titanium it said false :frown:.

r4_=[39,12,3] inches (vector from CG to T4 connection)
r5_=[-21,12,3] inches (vector from CG to T5 connection)
T4_=T4*[-.98,.098,-.172]
T5_=T5*[.98,.098,-.172]

I'll be putting this together in Abaqus while waiting for your comments. Halp!
 

Attachments

  • Floor Attachment Analysis.pdf
    Floor Attachment Analysis.pdf
    1.4 MB · Views: 436
  • photo (4).jpg
    photo (4).jpg
    19.6 KB · Views: 493
Physics news on Phys.org
No takers? It seems like a simple 3D statics problem, I just haven't had statics in a while.
 
Y'all are lame.

 
Dude I need numbers, and 4 is not enough.
 
rcgldr, I don't like you. You don't read. I had already figured out how I was attaching it, and needed magnitudes of the tension in the cables. Both of your posts were useless to me.

The correct answer was to simply add the third direction to my moment equation, I'm done now.

Mod, please close this forum.
 
Sorry, I couldn't download the pdf file the first time I tried, so I was just guessing at what you wanted since no one else responded. I tried and again and was able to see the pdf file, so I understand you question now, but you've already solved it.
 
It's cool I appreciate your comments. I've never seen this board so mute with such a simple question. Probably a TL;DR situation.