I'm sorry I can't get what you mean. How does the compressive member come?PhanthomJay said:You can't always tell by inspection, but in this simple case, does the leg on the right get pushed down or pulled up when the load is applied as shown? How about what happens to the other leg?
Compressive forces are 'pushing' forces and tensile forces are 'pulling' forces. Take 2 popsicle sticks and fasten them at one end in the shape of the upside down V as in your problem ( ^ ). Set the legs on a table and apply the rightward horizontal force at the top. One of the legs will pull off the table, while the other leg will push on the table. Which is which? The one that pulls would be in tension if anchored to the table, and the one that pushes will be in compression.Dave1357 said:I'm sorry I can't get what you mean. How does the compressive member come?
Oh, I understand. Thanks a lot !PhanthomJay said:Compressive forces are 'pushing' forces and tensile forces are 'pulling' forces. Take 2 popsicle sticks and fasten them at one end in the shape of the upside down V as in your problem ( ^ ). Set the legs on a table and apply the rightward horizontal force at the top. One of the legs will pull off the table, while the other leg will push on the table. Which is which? The one that pulls would be in tension if anchored to the table, and the one that pushes will be in compression.
They can be a bit more complex, but, yes, that is best. Try to visualize when you can, then run the numbers.Dave1357 said:Oh, I understand. Thanks a lot !
So, this kind of checking can only be applied on simple case like the above, right?
If there are complicated trusses, we must use method of joint/section to calculate.
A simple truss problem involves analyzing a structure composed of straight members connected at their ends by frictionless pins or hinges. The goal is to determine the forces acting on each member in order to ensure the stability and safety of the structure.
In order to identify compression and tension in a truss, you must first draw a free body diagram for each joint. Then, you can use the method of joints or the method of sections to analyze the forces acting on each joint. Compression forces will push on the joint, while tension forces will pull on the joint.
Compression and tension are two types of forces that act on a structure. Compression forces are inward forces that push on a structure, while tension forces are outward forces that pull on a structure. Both forces are necessary for the stability and balance of a structure.
To calculate the forces in a truss, you can use the equations of equilibrium, which state that the sum of all forces in the x and y directions must equal zero. By setting up and solving equations for each joint, you can determine the forces in each member of the truss.
Some common mistakes when solving simple truss problems include not drawing accurate free body diagrams, not considering all forces acting on a joint, and not applying the equations of equilibrium correctly. It is also important to double check your calculations and ensure that they make sense in the context of the problem.