1. Chapter 9 Welding, Bonding, and the Design of Permanent Joints
Dr. A. Aziz Bazoune
King Fahd University of Petroleum & Minerals
Mechanical Engineering Department
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

2. Chapter Outline 9-1 Welding Symbols 9-2 Butt and Fillet Welds
9-3 Stresses in Welded Joints in Torsion
9-4 Stresses in Welded Joints in Bending
9-5 The Strength of Welded Joints
9-6 Static Loading
9-7 Fatigue Loading
9-8 Resistance Welding
9-9 Bolted and Riveted Joints Loaded in Shear
9-10 Adhesive Bonding
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

3. LECTURE-40 9-4 Stresses in Welded Joints in Bending
9-5 The Strength of Welded Joints
9-6 Static Loading
9-7 Fatigue Loading
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

4. 9-4 Stresses in Welded Joints in Bending
Fig. 9-17a shows a cantilever welded to a support by fillet welds at top and bottom.
A FBD diagram of the beam would show a shear force V and a moment diagram M.
The shear force produces a primary shear in the welds of magnitude
The moment M introduces a throat shear stress component of τ in the welds.
Treating the two welds of Fig. 9-17b as lines we find the second moment of area to be
(a)
(b)
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

5. 9-4 Stresses in Welded Joints in Bending
The second moment of area I, based on weld throat area, is
The nominal throat shear stress is now found to be
The model gives the coefficient of 1.414, in contrast to the predictions of Sec.9-2 of from distortion energy, or from maximum shear.
The second moment of area in Eq. (d) is based on the distance d between the two welds.
(c)
(d)
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

6. Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

7. 9-5 The Strength of Welded Joints
The matching of the electrode properties with those of parent metal is usually not so important as speed, operator appeal, and the appearance of the completed joint.
The properties of electrodes vary considerably, but Table 9-3 lists the minimum properties for some electrode classes.
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

8. For these ASTM steels, Sy = 0.5 Su.
It is preferable, in designing welded components, to select a steel that ill result in a fast, economical weld.
Best results are obtained for steels having a UNS specifications between G10140 and G10230.
All these steels have a tensile strength in the hot-rolled condition in the range of 60 to 70 kpsi.
Permissible stresses are now based on the yield strength of the material instead of the ultimate strength, and the code permits the use of a variety of ASTM structural steels having yield strengths varying from 33 to 50 kpsi.
For these ASTM steels, Sy = 0.5 Su.
Table 9-4 lists the formulas specified by the code for calculating these permissible stresses for various load conditions.
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

9. Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

10. The fatigue stress concentration factors listed in Table 9-5 are suggested for use. These factors should be used for the parent metal as well as for the weld metal.
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

11. Table 9-6 gives steady-load information and minimum fillet sizes.
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

12. 9-6 Static Loading Table A-20, Sy = 27.5 kpsi Example 9-2 (Textbook)
h =3/8=0.375 in
t = 1/2 in
l = 2 in
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

13. Example 9-2 (Cont.’d) h =3/8=0.375 in t = 1/2 in l = 2 in
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

14. Example 9-4 (Textbook) Table 9-2, pattern 2, b=3/8 = 0.375 in
Table A-20,
Sy = 32 kpsi, Sut= 58 kpsi
Example 9-4 (Textbook)
Table 9-3,
Sy = 50 kpsi,
Sut= 62 kpsi
Table 9-2, pattern 2, b=3/8 = in
and d= 2in
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

15. Eq. 6-21 Ssy= 0.577 Sy E6010 electrode Table 9-3, Sy = 50 kpsi,
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

16. Given n=3
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

17. 9-7 Fatigue Loading The conventional methods will be provided here.
In fatigue, the Gerber criterion is best; however, you will find that the Goodman criterion is in common use.
Recall, that the fatigue stress concentration factors are given in Table 9-5.
For Welding codes, see the fatigue stress allowables in the AISI manual.
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

18. Example 9-5 (Textbook) Table A-20, Sy = 32 kpsi, Sut= 58 kpsi
Kfs=2.7
Table 9-3,
Sy = 62 kpsi, Sut= 50 kpsi
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

19. A = 2 x 0.707 x h x l h = 3/8=0.375 in l = 2 in (7-8) (7-17) (7-4)
(7-25)
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

20. Example 9-6 (Textbook)
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

21. (7-4)
(7-8)
(7-25)
(7-17)
(7-56)
(7-10)
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

22. QUESTIONS ?
Thank U !
Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints

23. Dr. A. Aziz Bazoune Chapter 9: Welding, Bonding, and the Design of Permanent Joints