Tensile and shear stress in 10mm rivet

[chris78]

Homework Statement

A load P of 3kN is applied to the tensile member shown and is carried at the joint by
a single rivet. The angle of the shear joint is 45 degrees to the axis of the load. Calculate
the tensile and shear stresses in a 10mm diameter rivet

Homework Equations

The Attempt at a Solution

Work out Shear force:
[/B]
Shear force 3sin45=2.121kn

Work out tensile force:

Tensile force=3cos45=2.12kn

Tensile stress= force/area

=2121.3/7.853x10^-5
=27009236.08 nm/^2
=27 mn/m2

Shear stress will be the same

I have atttached an image of the question and also my workings out. I am being told that this is incorrect by my tutor...but have been racking my brains to why! Is the resolved triangle in my workings wrong?

Any help would be brilliant as I am not sure where/if I am going wrong!

Thanks

 

[BvU]

Well, post what you have done ! An illegible sunny picture doesn't help.

[aside:] And don't trust the exercise composer: he/she tries to sell you a 45 degree angle that's clearly drawn at 60 degrees

 

[chris78]

I have posted my workings...within the post as well as 'illegible' scribblings...the problem states 45 degrees ?

 

[PhanthomJay]

I have posted my workings...within the post as well as 'illegible' scribblings...the problem states 45 degrees ?

The book solution uses 45 degrees ...answer given is correct for shear and tensile stress. Your answer agrees except be sure to write it properly as 27 MN/m².

 

[chris78]

Hi there

Thankyou for you reply...when I handed this in my tutor said I was wrong..but I have been racking my brains to see why...that's why I posted a picture of my workings with my vector triangle to make sure my method is correct

 

[chris78]

The book solution uses 45 degrees ...answer given is correct for shear and tensile stress. Your answer agrees except be sure to write it properly as 27 MN/m².

Thanks for your help...i have just posted another similar question regarding this subject...is it possible you could have a look at it for me,and tell me if I am on the correct lines? Again,thanks for your help.

 

[PhanthomJay]

You're welcome.