Ao
Recall t* = ln Ai*
Ao
Ai*
t* Ai*= Pmax
= et*
AiAi*= Aoe-t*
Pmax = t* Ai*
o)
n
0.46/1.125 = 0.41
40,000 psi
X
Because material went beyond max. load
~13,000 lbs
1.46
t = ln ( nom + 1)
nom = et 1 = e - 1 = 1.46
Pmax = t* Aoe-t* = x e-
t
What is nomin

In-class Problem
A thin Zirconia ceramic-coating is used to protect relatively tough Inconel 718
turbine-blade shown. What stress is experienced by the coating if the temperature
changes from an ambient 200C to a maximum of 8000C?
Assume t=0.254mm, h=2.54

In-class problem 3
You are designing a member with a U shaped notch identical to the
one seen in the sketch below. Your member has the following
dimensions: D =2.25 in, d =1.5 in, h =0.25 in, r = 0.3. From the
information presented on the graph determine:

Mechanical Response of Engineering
Materials: EMch 315
Stress Concentration Factors
Lecture 8
Chapter 2.11 : Mechanical Response of Engineering Materials
1
Stress Concentration Factors
Geometric discontinuities cause an object to
experience a local increa

Mechanical Response of
Engineering Materials:
EMch 315
Plastic Deformation & Ductile Failure I
Lecture 14
Chapter 6
(Mechanical Response of Engineering Materials)
1
Introduction
Aero planes, automobiles, building structures use finished products
such as s

Mechanical Response of
Engineering Materials:
EMch 315
Analysis of Stress I
Lectures 6
Chapter 2
Mechanical Response of Engineering Materials
1
Objectives
For plane-stress, develop the equations for
transformation of axes, and apply them to
determine pri

Mechanical Response of
Engineering Materials:
EMch 315
Fatigue and Related Failures II
Lecture 20
Chapter 8 :
Mechanical Response of Engineering Materials
1
Stress Fluctuation and Cumulative Damage Concepts
In addition to constant mean stress, stress cond

Mechanical Response of Engineering
Materials: EMch 315
Viscoelasticity of Materials
Lectures 22, 23, 24 Chapter 9
(Mechanical Response of Engineering Materials)
1
Viscoelasticity
Definition: Viscoelasticity is the relationship among time, strain/stress,
a

Mechanical Response of
Engineering Materials:
E Mch 315
Elastic Behavior of Materials
Lecture 4
Chapter 3
(Mechanical Response of Engineering Materials)
1
Load, pounds, F
L0 = 2 inch
D = 0.505 inch
2
A0 = p(0.505/2)2 = 0.2 in
4000
3000
2000
4025 sy
spl
E

Mechanical Response of
Engineering Materials:
EMch 315
The Analysis of Strain I
Lecture 9
Chapter 1
(Mechanical Response of
Engineering Materials)
1
The Analysis of Strain
All solids undergo deformation under the action of
loads (forces/moments/temperatur

How to Draw Mohrs Circle in
3-D
Supplement to Lecture 7
Mohrs Circle
method to transform stresses/strains from
one coordinate system to another system.
Real space: x, y, z
Mohr space: I, II, III
2
3-Dimensional Stress Transformations
0
xx xy
yx yy 0

Mechanical Response of Engineering
Materials: EMch
315
Tensile and Compressive
Properties III
Lecture 3
Chapter 4 : Mechanical Response of
Engineering Materials
1
What has been learnt from stress-strain curve so far?
Young/Elastic Modulus (E): Slope of l

Mechanical Response of
Engineering Materials:
EMch 315
Fatigue and Related Failures III
Lecture 21
Chapter 8 :
Mechanical Response of Engineering Materials
1
Fatigue Fractography
When material failure involves actual
breakage, fractography can be employed

Mechanical Response of
Engineering Materials:
EMch 315
Yielding for Multiaxial Stress
States (Safe Design) I
Lecture 11
Chapter 5
(Mechanical Response of Engineering Materials)
1
Yielding for Multiaxial
Stress States:
Chapter 5
Engineering components are

Mechanical Response of
Engineering Materials:
EMch 315
Analysis of Stress II
Lectures 7
Chapter 2
(Mechanical Response of Engineering Materials)
1
3-Dimensional Stress Transformations
yy
We started our discussion of stress
analysis by emphasizing the plan

Example 1: A 130B Ti machine member is subjected to the following stress history each
day. Find the maximum number of days where 50% will not have failed in fatigue using
the S-N curve on the below. Assume that uts=155Ksi.
Goodmans Eqn
di = ni / Ni
a = (

Ao
Recall t* = ln Ai*
Ao
Ai*
t* Ai*= Pmax
= et*
AiAi*= Aoe-t*
Pmax = t* Ai*
o)
n
0.46/1.125 = 0.41
40,000 psi
X
Because material went beyond max. load
~13,000 lbs
1.46
t = ln ( nom + 1)
nom = et 1 = e - 1 = 1.46
Pmax = t* Aoe-t* = x e-
t
What is nomin

Mechanical Response of
Engineering Materials:
EMch 315
The Analysis of Strain I
Lecture 9
Chapter 1
(Mechanical Response of
Engineering Materials)
1
The Analysis of Strain
All solids undergo deformation under the action of
loads (forces/moments/temperatur

Mechanical Response of Engineering
Materials: EMch 315
Stress Concentration Factors
Lecture 8
Chapter 2.11 : Mechanical Response of Engineering Materials
1
Stress Concentration Factors
Geometric discontinuities cause an object to
experience a local increa

Mechanical Response of
Engineering Materials:
EMch 315
Analysis of Stress II
Lectures 7
Chapter 2
(Mechanical Response of Engineering Materials)
1
3-Dimensional Stress Transformations
yy
We started our discussion of stress
analysis by emphasizing the plan

Mechanical Response of
Engineering Materials:
EMch 315
Analysis of Stress I
Lectures 6
Chapter 2
Mechanical Response of Engineering Materials
1
Objectives
For plane-stress, develop the equations for
transformation of axes, and apply them to
determine pri

Mechanical Response of Engineering
Materials: EMch 315
Tensile and Compressive
Properties I, II, III
Lectures 1, 2 and 3
Chapter 4 : Mechanical Response of
Engineering Materials
1
Topics Covered in EMch 315
Introduction
Tensile and Compressive Response (C

Mechanical Response of
Engineering Materials:
E Mch 315
Elastic Behavior of Materials
Thermal Stresses and Strains
Lectures 4 and 5
Chapter 3
(Mechanical Response of Engineering Materials)
1
Elastic Response
Materials ability to return to its original len

ij
2
5
1
5
0
k
s
i
0
In-class problem 1
The solid shaft shown below has a radius of 0.5 in. and is made of steel having a yield
strength of y = 36 ksi. Determine if the loading causes the shaft to fail according to
the maximum-shear-stress theory (MSST)

In-class Problem
The stress-strain curve for an aluminum alloy used for aircraft parts is
shown below. If a specimen of this materials is stressed to 600 MPa,
determine the permanent strain that remains in the specimen when the load
is released.
Slope of

In-class Problem
3.1. What elastic volume changes to a rail car hub are induced by the following applied stress state?
Assume the hub is constructed from an isotropic steel with E = 210 GPa and = 0.28.
600 -320 0
ij = -320 150 0
0
0 -280
MPa
Since shear