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Help needed: tube fatigue failure stress at clamp point calculation needed
[FONT=Arial][COLOR=#000000]Hi [/COLOR][/FONT]
[FONT=Arial][COLOR=#000000]I am experiencing a fatigue failure of grease tubes at bracket points. The brackets are steel and crush the pipe, which is on a vehicle so experiences high levels of vibration. Table shows main info, attached image shows stress I am searching for (bracket redesign probable, but I also need to find this value beforehand). Thank you for your help.
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="width: 291, bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]Tube OD[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="width: 118, bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]12mm[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]Tube ID[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]10mm[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]Tensile Strength[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]480 MPa[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][SIZE=3][COLOR=#000000][FONT=MS Pゴシック]Yield Strength [/FONT][/COLOR][/SIZE][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]325 Mpa[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]Youngs Mod (E)[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]200GPa[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][SIZE=3][COLOR=#000000][FONT=MS Pゴシック]Measured Vibration [/FONT][/COLOR][/SIZE][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]6g[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]Mass tube and grease[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]0.342kg/m[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]Clamping force[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]515MPa[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][SIZE=3][COLOR=#000000][FONT=MS Pゴシック]Deformation with clamping [/FONT][/COLOR][/SIZE][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]8% OD[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]Max dist clamp - clamp[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]1100mm[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]Bolt torque (M10 bolt)[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]54000Nmm[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="width: 291, bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]*Clamping force (from above)[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]36072 N[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="width: 291, bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]*Clamping pressure (assuming 1mm contact of tube against clamp due to crushing)[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]515MPa[/COLOR][/SIZE][/FONT][/TD]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]* Moment of inertia of uncrushed tube[/COLOR][/SIZE][/FONT][/TD]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][TD="bgcolor: white"][FONT=MS Pゴシック][SIZE=3][COLOR=#000000]* 5.27E-10 m^4[/COLOR][/SIZE][/FONT][/TD]
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