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    Chapter 1 (1-1)

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    Gnabry
    This document provides an overview of forces and their effects on materials. It defines key terms like stress, strain, and modulus of elasticity. Stress is defined as the force applied over an area. Strain is the ratio of change in length to the original length. The modulus of elasticity describes the relationship between stress and strain in the elastic deformation region of materials. Examples are provided to demonstrate how to calculate stress, strain, and modulus of elasticity values.

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    Chapter 1 (1-1)

    Uploaded by

    Gnabry
    14 views42 pages
    This document provides an overview of forces and their effects on materials. It defines key terms like stress, strain, and modulus of elasticity. Stress is defined as the force applied over an area. Strain is the ratio of change in length to the original length. The modulus of elasticity describes the relationship between stress and strain in the elastic deformation region of materials. Examples are provided to demonstrate how to calculate stress, strain, and modulus of elasticity values.

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    CHAPTER 1(1-1)

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    This document provides an overview of forces and their effects on materials. It defines key terms like stress, strain, and modulus of elasticity. Stress is defined as the force applied over an area. Strain is the ratio of change in length to the original length. The modulus of elasticity describes the relationship between stress and strain in the elastic deformation region of materials. Examples are provided to demonstrate how to calculate stress, strain, and modulus of elasticity values.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    14 views42 pages

    Chapter 1 (1-1)

    Uploaded by

    Gnabry
    This document provides an overview of forces and their effects on materials. It defines key terms like stress, strain, and modulus of elasticity. Stress is defined as the force applied over an area. Strain is the ratio of change in length to the original length. The modulus of elasticity describes the relationship between stress and strain in the elastic deformation region of materials. Examples are provided to demonstrate how to calculate stress, strain, and modulus of elasticity values.

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    © All Rights Reserved
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    Download as pdf or txt
    of 42

    CHAPTER 1

    FORCES ON THE MATERIAL

    PREPARED BY ADIANI BINTI AB RAHMAN


    OUTLINE
     TYPE OF APPLIED LOADS
     TYPE OF FORCES
     STRESS
     STRAIN
     MODULUS OF ELASTICITY
    Forces and Their Effects
    You cannot see a
    force but you can
    see what it does.
    You can also feel
    the effect of a
    force on your
    body.
    A force is a push or a pull
    What can a force do?

    A force can A force can


    make an object make a moving
    move. object stop
    What can a force do?

    A force can A force can


    changethe changethe
    direction of a shape of an
    moving object. object
    What can a force do?
    A force can
    change the speed
    of a movingobject.
    A force can accelerate an object. The larger the force
    on the object, the greater the acceleration if the mass
    stays constant. The larger the mass of the object, the
    smaller the acceleration if the force stays constant.

    Newton’s Second Law of Motion:


    Force (N) = mass (kg) x acceleration
    (m/s2)
    Strength of Materials :
    - Its ability to withstand an applied stress
    without failure (tensile, compressive and shear)
    - Deals with loads, deformations and the forces
    acting on a material.
    Tacoma Narrows Bridge
     7 Nov 1940 Washington
    Tacoma
    Narrows
    Bridge
    Collapse

    Shocking
    Disasters
    Happen
    When You
    Don’t Follow
    Engineering
    Safety
    Measures
    Balloon Stretch
    Types of load and its impact
    Static loading
    - A non varying
    load
    - The effect of
    gravity on an
    object or
    structure
    Types of load and its impact
    Dynamic loading
    - The forces that
    move or change
    when acting on a
    structure
    Types of load and its impact
    Impact loading
    - A force
    delivered by a
    blow, as opposed
    to a force applied
    gradually and
    maintained over
    a long period.
    Types of load and its impact
    Fatigue loading
    - a varying load
    superimposed on
    a constant load
    - only occur at
    certain times
    (spring)
    Types of load and its impact
    Alternating loading
    - place on the shaft
    which was used in
    power transmission
    Force Effect
    Types of force
    Types of force
    FORCE STRUCTURE PARTICLES
    Compressive
    Force

    Tensile Force

    Shear Force
    Types of force
    FORCE STRUCTURE PARTICLES

    Bending

    Torsion
    STRESS
    An applied force or system of forces that tends to
    strain or deform a body. "the intensity of stress is
    expressed in units of force divided by units of area"
    STRESS
    N
    Force applied to the
    P material
    σ=
    A over
    the Area of contact.

    N/m² @ Pa m²
    STRESS
    Example 1.1:
    A 50kN of extensive load act on the bar as
    below. Calculate the value of stress.

    0.07
    0.02 m
    m
    50 kN 50 kN

    200 mm
    STRESS
    Solution:
    STRESS
    Example 1.2:
    A Steel rod with a diameter of 25 mm have
    an applied force of 4 kN on its axis.
    Determine the stresses that occur in the
    rod.

    4 kN 4 kN
    STRESS
    Solution:
    STRAIN
    The ratio of the change in length caused by the applied
    force, to the original length.

    m
    of elongation or
    contraction of the
    ∆L material
    ε= ratio
    L to its original
    length.
    m
    Terminology
     Extension- change in length
     Extended length- total length with load
    applied
    Natural length

    Extended length

    Force
    Applied
    Extension
    Fill out the table for the springs
    10
    cm
    4 cm
    4 cm
    2N 4 cm
    4N
    6N

    Force Applied Extended Length Extension of


    (N) of spring (cm) spring (cm)
    0 10 0
    2 14 4
    4 18 8
    6 22 12
    STRAIN
    Example 1.3:
    Calculate the strain value of the bar.

    0.02 m

    50 kN 50 kN

    200 mm

    210
    mm
    STRAIN
    Solution:
    STRAIN
    Example 1.4:
    A bar with 0.065m of length been given force
    resulting the bar to increase its length by
    0.05mm. Calculate the strain value of the bar.
    STRAIN
    Solution:
    MODULUS OF ELASTICITY
    Elasticity and Plasticity
    All materials will behave elastically or plastically-
     For elastic behaviour – when a force is
    applied the change in length is proportional to
    the force. The object will return to its original
    shape when the force is taken away.
     For plastic behaviour – the force and the
    change of length are not linked. A permanent
    deformation occurs when the force is taken
    away.
    Elasticity and Plasticity
    Force

    2.

    1. Elastic Limit
    Extension

    1. Elastic region (any force applied below the elastic limit)


    2. Plastic region (any force applied above the elastic limit)
    MODULUS OF ELASTICITY
    𝛔
    𝐄=
    𝛆 HOW??
    PROVE IT!

    𝐏𝐋
    𝐄=
    𝐀∆𝐋

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