The discussion revolves around solving mechanics problems related to framed structures, specifically focusing on a trapezoidal-shaped metallic billboard attached to an inverted L-shaped framework. Participants are addressing the steps required to analyze the forces and moments acting on the structure, including drawing free-body diagrams and determining shear forces and bending moments.
Participants generally agree on the need to analyze the forces and moments acting on the structure, but there are multiple competing views on how to approach the problem, particularly regarding the correct representation of forces in free-body diagrams and the calculations involved. The discussion remains unresolved as participants provide various suggestions and corrections without reaching a consensus.
Some participants note that the problem is statically determinate, which allows for self-checking of the calculations. However, there are unresolved issues regarding the correct identification of forces and moments, as well as the assumptions made in the analysis.
It's somewhere around there, I didn't calc out the numbers, but yes, max bending stress is Mc/I where M is the max moment (139 Nm) occurring at the support, which controls the overall frame structural design. The I term comes from the properties of the hollow circle, and c is its outside radius.D44 said:Sorry, 44.24MPa
First draw it as a full frame to determine reactions at the fixed support at the base. Then break it up into the horizontal piece and slanted piece separately to determine forces and moments in each of those members.M3_CSL said:Hi, i am having the same trouble with this assignment, mainly drawing the free body diagram of each section. Not sure exactly whether to draw it as a full frame or two separate parts.
thanks
The vertical load is the area of the distributed loading diagram. It's a combimation of a rectangle 20 x 2.15 and a triangle with a long leg of 2.15 and a short leg of 20. Total = 64.5 N. The moment at the right hand side of the horizontal member is the equal and opposite of the moment about that point from the given applied loadings.M3_CSL said:Thanks, so for the horizontal piece, when your working out the vertical forces, how do you know whether to use the 20 N/m or 40 N/m [/color]? and does it only have 2 downward forces due to the billboard and one moment force due to the slanted piece?
Thank you