Question:
A hole in a pressure vessel end plate repair casting is being drilled using a radial arm drill. The distance from the drill point to the centre of the drill column is 1.2m. The drill column is a tube having internal and external diameters of 25cm and 30cm respectively. If the force on the drill point is 30kN sketch the stress distribution across the drill column.
![](https://static.wixstatic.com/media/20c892_b0c3d5fa61a949b3b6ceb1865bcd2fe5~mv2.png/v1/fill/w_49,h_18,al_c,q_85,usm_0.66_1.00_0.01,blur_2,enc_auto/20c892_b0c3d5fa61a949b3b6ceb1865bcd2fe5~mv2.png)
Answer:
![](https://static.wixstatic.com/media/20c892_59182f33cee040e191c2d263df946514~mv2.png/v1/fill/w_78,h_26,al_c,q_85,usm_0.66_1.00_0.01,blur_2,enc_auto/20c892_59182f33cee040e191c2d263df946514~mv2.png)
Max bending stress occurs on outer fibres.
![](https://static.wixstatic.com/media/20c892_a902555914a54a4b8f3402e7e0578c4c~mv2.png/v1/fill/w_78,h_15,al_c,q_85,usm_0.66_1.00_0.01,blur_2,enc_auto/20c892_a902555914a54a4b8f3402e7e0578c4c~mv2.png)
Left Edge stress calculation:
![](https://static.wixstatic.com/media/20c892_920be37a1b034800ac2fde0dbcb09e6c~mv2.png/v1/fill/w_79,h_4,al_c,q_85,usm_0.66_1.00_0.01,blur_2,enc_auto/20c892_920be37a1b034800ac2fde0dbcb09e6c~mv2.png)
Right Edge stress calculation:
![](https://static.wixstatic.com/media/20c892_38e79d59c4924c97b1f711fbbe7c1f60~mv2.png/v1/fill/w_79,h_4,al_c,q_85,usm_0.66_1.00_0.01,blur_2,enc_auto/20c892_38e79d59c4924c97b1f711fbbe7c1f60~mv2.png)
Stress distribution diagram:
![](https://static.wixstatic.com/media/20c892_1eeb80b807694b2084a546222b60de0f~mv2.png/v1/fill/w_85,h_38,al_c,q_85,usm_0.66_1.00_0.01,blur_2,enc_auto/20c892_1eeb80b807694b2084a546222b60de0f~mv2.png)