Simple Stress and Strain in Strength of Materials
38 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of stresses are tensile and compressive stresses referred to as?

  • Shear stresses
  • Bending stresses
  • Torsional stresses
  • Direct or Normal stresses (correct)

    • What is the direction of the force acting on the bar in compression?

  • Parallel to the bar
  • Perpendicular to the bar
  • Towards the bar (correct)
  • Away from the bar

    • What is the significance of the stress equation?

  • It gives the average normal stress (correct)
  • It gives the shear stress
  • It gives the maximum normal stress
  • It gives the minimum normal stress

    • What is the convention for defining tensile and compressive stresses?

    <p>Tensile stresses are defined as positive and compressive stresses as negative</p> Signup and view all the answers

    Why are tables and graphs used in stress concentration?

    <p>To determine the stress concentration factor K</p> Signup and view all the answers

    What is the relationship between the maximum stress and the average stress?

    <p>The maximum stress is K times the average stress</p> Signup and view all the answers

    What type of force is acting on the bar when it is stretched?

    <p>Tensile force</p> Signup and view all the answers

    What is the direction of the force acting on the bar when it is in compression?

    <p>Towards the bar</p> Signup and view all the answers

    What is the formula to calculate the stiffness, K, of an axially loaded bar?

    <p>K = P/δ</p> Signup and view all the answers

    What is the definition of flexibility, f, in structural analysis?

    <p>The deflection given to a unit load</p> Signup and view all the answers

    What is the formula to calculate the deflection, δ, of an axially loaded bar?

    <p>δ = PL/EA</p> Signup and view all the answers

    What is the unit of measurement for stiffness, K?

    <p>Newton per meter</p> Signup and view all the answers

    What type of load is considered in the analysis of axially loaded bars?

    <p>Axial load</p> Signup and view all the answers

    What is the relation between stiffness, K, and flexibility, f?

    <p>K is the reciprocal of f</p> Signup and view all the answers

    What is the percentage elongation defined as?

    <p>(Lf - Lo) / Lo</p> Signup and view all the answers

    What is the factor of safety normally defined as?

    <p>Ratio between the failure stress and the working stress</p> Signup and view all the answers

    What is the condition for a material to be classified as brittle?

    <p>Percentage elongation is less than 5 in a gauge length of 50 mm</p> Signup and view all the answers

    What is Hooke's Law applicable to?

    <p>Elastic region</p> Signup and view all the answers

    What is the allowable stress defined as for ductile materials with no well-defined yield stress?

    <p>0.5 * Failure stress / Factor of safety</p> Signup and view all the answers

    What is the percentage reduction defined as?

    <p>(Ao - Af) / Ao</p> Signup and view all the answers

    Why is a safety factor important in designing a structure?

    <p>To ensure the working stresses are within safe limits</p> Signup and view all the answers

    What is the allowable stress defined as for brittle materials?

    <p>Failure stress / Factor of safety</p> Signup and view all the answers

    What is the source of stresses and strains in a structure besides external loads?

    <p>Change in temperature</p> Signup and view all the answers

    What is the formula for strain energy of a non-prismatic bar with continuously varying axial force?

    <p>U = ∫(P.dx)/(2.AE)</p> Signup and view all the answers

    What is the unit of the modulus of elasticity E?

    <p>GPa</p> Signup and view all the answers

    Why do temperature changes cause stresses and strains in a structure?

    <p>Because the expansion and contraction is wholly or partially restricted</p> Signup and view all the answers

    What is the type of stress that occurs due to temperature changes?

    <p>Temperature stress</p> Signup and view all the answers

    What is the strain energy of a bar hanging vertically under its own weight given as?

    <p>U = ∫(P.dx)/(2.AE)</p> Signup and view all the answers

    What is the formula for strain energy of an axially loaded spring?

    <p>U = (1/2).(P^2)/(AE)</p> Signup and view all the answers

    What are the loads acting on the truss ABC?

    <p>A horizontal load of 9 kN and a vertical load of 18 kN</p> Signup and view all the answers

    What is the change in the right angle referred to as?

    <p>Shear strain</p> Signup and view all the answers

    What is the direction of the outward normal of a positive face?

    <p>Positive direction of a coordinate axis</p> Signup and view all the answers

    What is the sign of the shear stress acting on a positive face of an element if it acts in the negative direction of an axis?

    <p>Negative</p> Signup and view all the answers

    What happens to the angle between two positive or two negative faces when the shear strain is positive?

    <p>The angle is decreased</p> Signup and view all the answers

    What is the relationship between the shear stress and shear strain in the linear elastic region?

    <p>τ = Gγ</p> Signup and view all the answers

    What is the ratio of the shear stress to the shear strain?

    <p>Shearing modulus of elasticity</p> Signup and view all the answers

    What is the shape of the τ versus γ diagram?

    <p>Similar to the σ versus ε diagram</p> Signup and view all the answers

    What is the name of the material property that is the ratio of the shear stress to the shear strain?

    <p>Modulus of rigidity</p> Signup and view all the answers

    Study Notes

    Simple Stress and Strain

    • Stress can be either tensile or compressive, depending on the direction of the force applied to a metal bar
    • Tensile stresses are positive, while compressive stresses are negative
    • Direct or normal stresses are stresses that act perpendicular to the cut surface
    • The stress equation gives the average normal stress acting on the cross-sectional area
    • The maximum stress will depend on the bar's geometry and the type of discontinuity, and can be calculated using a stress concentration factor K

    Tensile-Test

    • A tensile test is used to determine the properties of a material under tension
    • The test involves stretching a metal bar until it fractures
    • The percentage elongation and percentage reduction of area can be calculated from the test results
    • A material is classified as brittle if the percentage elongation is less than 5 in a gauge length of 50 mm

    Factor of Safety

    • A factor of safety is used to ensure that the working stresses in a structure remain within safe limits
    • The factor of safety is defined as the ratio between the failure stress and the working stress
    • To avoid failure, the allowable stress must be less than or equal to the failure stress divided by the factor of safety

    Hooke's Law

    • Within the elastic region, there is a linear relationship between stress and strain
    • Hooke's Law is represented by the equation σ = Eε, where σ is the stress, E is the modulus of elasticity, and ε is the strain

    Axially Loaded Spring/Bars

    • The stiffness of an axially loaded bar is defined as the force required to produce a unit deflection
    • The flexibility of an axially loaded bar is defined as the deflection given to a unit load
    • The strain energy of an axially loaded bar can be calculated using the equation U = (1/2)Pδ

    Strain Energy

    • Strain energy is the energy stored in a deformed material
    • The strain energy of an axially loaded bar can be calculated using the equation U = (1/2)Pδ
    • The strain energy of a non-prismatic bar with continuously varying axial force can be calculated using the equation U = ∫(P^2/2EA)dx

    Temperature Stress and Shear Stress

    • Temperature changes can cause stresses and strains in a structure
    • Temperature stresses occur when the expansion or contraction of a material is restricted
    • Shear stresses occur when there is a change in the right angle at the corners of a face
    • Shear strain is defined as the change in the right angle at the corners of a face

    Shear Stress and Shear Strain

    • The relationship between shear stress and shear strain is similar to that between normal stress and normal strain
    • Within the linear elastic region, the shear stress and shear strain are directly proportional, and can be represented by the equation τ = Gγ
    • The shearing modulus of elasticity (modulus of rigidity) is defined as the ratio of the shear stress to the shear strain

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Strength of Material Slides PDF

    Description

    Quiz on simple stress and strain, including tension and compression, Poisson ratio, and strain energy. Important concepts in strength of materials.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser