Solving Problems 3 & 4: Looking for Alternatives

[nevadosajama]

Hi Guys attached is a pdf file with some problems that I've been solving, my question is if there is a better and/or different way to solve problems 3 and 4 (variations included).
Thanks in advance and cheers

 

[PhanthomJay]

On problem 3, you made a typo somewhere on your givens: In one place you say P3 is 1300 pounds, in another, you say its 1800 pounds.

I don't see your work in the attachment. Looks like you're finding the force in each section, then what? I assume you're adding/subtracting the deformations for each segment based on the internal forces in that section over that segment length?? If so, that's OK, but alternatively, you could just find the deformation at the end of the bar for each load P1, P2, and P3 separately, then add them up by superposition. This avoids having to find the internal forces . Just saves a small step, but the internal forces are good to know anyway, but this alternate approach will serve as a check. And my guess that this alternate approach is easier when you attempt to solve the value of P3 that will give zero total deformation.

I haven't looked at (4) yet... perhaps someone else will if I don't get to it.

Oh BTW, welcome to PF!

 

[nevadosajama]

Thanks Phantom Jay, yep, you're right I made a typo on the pdf file, (the pdf file is my work, I created the graphics on Deneba Canvas, and saved on pdf), I'll try your advice.
Thanks

 

[PhanthomJay]

Thanks Phantom Jay, yep, you're right I made a typo on the pdf file, (the pdf file is my work, I created the graphics on Deneba Canvas, and saved on pdf), I'll try your advice.
Thanks

I looked at number 4, and although I didn't check your numbers, your method looks perfect. I must also say that the clarity and neatness and presentation of your work is amongst the best I've ever seen. Nice job!