This document discusses welded connections. It begins by defining welding as the process of joining metals through heating and applying pressure or filler material. The document then covers the advantages and disadvantages of welded connections, different welding processes, types of welded joints including butt and fillet joints, stresses in welded joints, analyzing unsymmetrical welded sections under axial loads, and special cases of fillet joints subjected to torque or bending moments. Equations for calculating forces and stresses in various welded joint configurations are provided.

1. Teli Prakash(150990119050)
Thakur Shivam(150990119051)
Tripathi Himanshu(150990119052)
Vansia Mitrajsinh(150990119054)
Vasava Bhavik(150990119055)

2.  1) INTRODUCTION
 2) ADVANTAGES & DISADVANTAGES OF
WELDED CONNECTIONS
 3) TYPES OF WELDING PROCESSES
 4) TYPES OF WELDED JOINTS
 5) STRESSES & STRESS CONCENTRATION
FACTORS OF WELDED JOINTS
 6) ANALYSIS OF UNSYMMETRICAL WELDED
SECTIONS WHICH ARE AXIALLY LOADED
 7) SPECIAL CASES OF FILLET JOINTS

3.  The process of permanently joining two or
more metal parts by the fusion of edges of
the metals with or without applying pressure
and a filler material is called welding
 If pressure is applied  Forge welding
 Without pressure, with a separate weld
metal Fusion welding
 In a fusion welding, heat of melting is
obtained by two ways:- a) Gas heating b)
Electric arc

4.  Advantages:-
 1. Comparatively lighter than riveted
structures
 2) Greater strength compared to riveted
joints
 3) Addition and alterations can be done
easily
 4) Better finish than riveted joints. Hence
maintenance costs and painting costs are less
 5) Lesser time consuming
 6) Tension members are not weakened in
welded joints compared to riveted joints

5.  Disadvantages:-
 1) Requires skilled labour
 2) Possibility of additional stress
development due to uneven heating and
cooling. Or in other words, the members may
get distorted
 3) Testing is difficult.
 4) As there is no provision for expansion or
contraction of joints, cracks may develop
and propogate

6.  The two important types of welded joints
are:-
 1. Butt weld
 2. Lap (Fillet joint)
3.1) Butt weld joint:-
If the edges of the two plates are touching
each other and are joined by welding, then
the joint is called butt weld joint

7.  Let l= length of weld
t= Depth of weld
F=Tensile force
σt= Allowable tensile stress
 The tensile force, F= σt x A= σt x l x t

8.  Types of butt welds are
 A) Single V butt joint
 B) Double V butt joint
 C) Single U butt joint
 D) Double U butt joint

9.  3.2) Fillet weld or lap joint
 When the two members are overlapped and
joined by welding, then the joint is called
fillet weld joint

10.  Let l= length of weld
t= Throat thickness
s= Size of weld
F=Tensile force
σt= Allowable tensile stress for weld metal

11.  Throat thickness= AB sin45=s x 0.707
 Throat area (minimum area of weld)= Length
of weld x throat thickness= l x s x 0.707
 Tensile strength of the joint/ maximum
tensile force which the fillet joint can take
P=Allowable tensile stress of the weld x
throat area= σt x0.707 x l x s
 Tensile strength of the joint for double fillet
weld= 2 x σt x0.707 x l x s= 1.414 x σt xl x s

12.  3.3) Strength of parallel fillet joint
 Parallel fillet welds are designed for shear
strength
 Consider a double parallel fillet joint as
shown below

13.  If τ is the allowable shear stress of the weld
metal, then the weld strength (shear
strength) of the joint is F= Allowable shear
stress x throat area= 2 x 0.707 x s x l x τ
 Consider a combination of transverse fillet
weld and parallel fillet weld

14.  If τ is the allowable shear stress of the weld
metal and σt is the allowable tensile stress
of the weld metal, then the weld strength
(shear strength) of the joint is F = σt x l1 x
0.707 x s + τ x l2 x 1.414 x s
 For re-inforced welded joints, the throat
dimensions may be taken as 0.85 times the
plate thickness

16.  Consider an unsymmetrical section (angle)
welded on flange edges subjected to an axial
loading
 Let la = length of the weld at the top
 lb = length of weld at the bottom
 L= total length of weld= la+lb

17.  P= Axial load
 a= Distance of the top weld from an axis
passing through the CG of the angle (known
as the gravity axis)
 b= Distance of the bottom weld from gravity
axis.
 f= Resistance offered by the weld per unit
length.
 Resistance offered by top weld= f x la

18.  Moment of the resistance offered by top
weld about the gravity axis= f x la x a
 Similarly the moment of resistance offered
by the bottom weld about the gravity axis= f
x lb x b
 For equilibrium, sum of these moments
should be zero.
 Hence f x la x a= f x lb x b
 => la x a= lb x b; l= la + lb
 Hence la= l x b / (a+ b) and lb = l x a/(a + b)

19.  6.1) Circular fillet weld subjected to
torque/ torsion
 Consider a circular rod connected to a rogid
plate by a fillet joint as shown below.

20.  Let
d= Diameter of the rod
r= Radius of the rod
T= Torque applied
s=Size of weld/ weld leg size
t= Throat thickness
 J= Polar moment of inertia of the weld
section= ∏d³t/4

21.  According to torsion equation, Maximum
shear stress generated due to torsion τ=T.r/J
 τ= T x 2/∏d²t.
 Throat thickness, t=s x 0.707
 Hence τ= 2T/(∏d² x s x0.707)
 => τ= 2.83T/∏d²s
 6.2) Circular fillet weld subjected to
bending moment
 Consider a circular rod connected to a rigid
plate by a fillet weld as shown below

22.  Let M be the bending moment to which the
weld/rod is subjected to and Z be the section
modulus.
 Z= ∏d²t/4
 Bending stress σb= M/Z= (4 x M)/ ∏d²t
 t=s x 0.707
 Hence b=5.66M/ ∏d²s