INTRODUCTION TO MATERIAL TESTING

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• Q1: State the mechanical properties of materials.
  Ans: The mechanical properties of materials include:

  • ➔ Hardness
  • ➔ Toughness
  • ➔ Resilience
  • ➔ Stiffness
  • ➔ Ductility
  • ➔ Brittleness
  • ➔ Malleability
  • ➔ Elasticity
  • ➔ Plasticity
  • ➔ Wear resistance
• Q2: Define hardness of material.
  Ans: The hardness of material tells about how hard or soft something is. It is resistance against indentation.
• Q3: Define Rebound Hardness.
  Ans: Rebound hardness measures the height a standardized indenter bounces back after striking the material.
  OR
  Rebound hardness shows how high a small tool bounces back after hitting a material
• Q4: Define Indentation Hardness.
  Ans: Indentation hardness measures the resistance of a material to deformation from a penetrator under a known load.
  OR
  Indentation hardness shows how well a material resists being pressed or dented by a tool.
• Q5: Define Scratch line Hardness.
  Ans: Scratch line hardness measures the resistance of a material to being scratched by a harder object.
  OR
  Scratch hardness shows how well a material resists being scratched by a harder object.
• Q6: Define Wear Hardness.
  Ans: Wear hardness is the ability of a material to resist surface deterioration due to friction or rubbing.
• Q7: Define Toughness.
  Ans: Toughness is the ability of a material to absorb energy and deform plastically before breaking.
• Q8: Define Resilience.
  Ans: Resilience is the ability of a material to absorb energy when it is elastically deformed and release that energy upon unloading.
• Q9: Define Stiffness.
  Ans: Stiffness is the resistance of a material to deformation under applied force.
• Q10: Define Ductility.
  Ans: Ductility is the ability of a material to undergo permanent deformation under tensile stress without fracture.
• Q11: Define Brittleness.
  Ans: Brittleness is the tendency of a material to break or fracture without significant plastic deformation.
• Q12: Define Malleability.
  Ans: Malleability is the ability of a material to be hammered or rolled into thin sheets without cracking.
• Q13: Define Elasticity.
  Ans: Elasticity is the ability of a material to return to its original shape after removal of applied load.
• Q14: Define Plasticity.
  Ans: Plasticity is the ability of a material to undergo permanent deformation without breaking when a load is applied.
• Q15: What is a Tensile Test?
  Ans: A tensile test is an experiment in which a material is subjected to a uniaxial tensile load to determine its mechanical properties like strength, ductility, and elongation.
• Q16: What is a Compression Test?
  Ans: A compression test is an experiment in which a material is subjected to compressive load to determine its behavior under crushing or shortening.
• Q17: Define Necking.
  Ans: Necking is the localized reduction in cross-sectional area of a material specimen under tensile load just before fracture.
• Q18: What is a Stress-Strain Diagram?
  Ans: A stress-strain diagram is a graph that shows the relationship between the applied stress and the resulting strain of a material under load.
• Q19: What is an Extensometer?
  Ans: An extensometer is a device used to measure the small changes in length (strain) of a specimen during a tensile test.
• Q20: Define Proportional Limit.
  Ans: Proportional limit is the maximum stress up to which stress is directly proportional to strain in a material. Beyond this, Hooke's Law does not hold.
• Q21: Define Elastic Limit.
  Ans: Elastic limit is the maximum stress a material can withstand without permanent deformation. The material returns to its original shape if stress is removed.
• Q22: Define Yield Point.
  Ans: Yield point is the stress at which a material begins to deform plastically. Beyond this point, permanent deformation occurs.
• Q23: Define Ultimate Tensile Stress.
  Ans: Ultimate tensile stress (UTS) is the maximum stress a material can withstand before necking or failure occurs.
• Q24: Define Breaking Stress.
  Ans: Breaking stress is the stress at which a material actually fractures or breaks under load.
• Q25: Define Point of Fracture.
  Ans: Point of fracture is the exact point on the stress-strain curve where the material separates into two pieces.
• Q26: Define Material Testing.
  Ans: Material testing is the process of evaluating a material’s mechanical, chemical, and physical properties to determine its suitability for engineering applications.
• Q27: What is a Destructive Test of Materials?
  Ans: A destructive test is a test in which the material is subjected to stress until it fails or breaks to study its mechanical properties.
• Q28: Name 4 Destructive Tests for Metals.
  Ans: The 4 destructive tests for metals are:

  • ➔ Tensile Test
  • ➔ Compression Test
  • ➔ Bending Test
  • ➔ Impact Test (Charpy or Izod)
• Q29: Name 4 Destructive Tests for Concrete.
  Ans: The 4 destructive tests for concrete are:

  • ➔ Compressive Strength Test
  • ➔ Flexural Strength Test
  • ➔ Split Tensile Test
  • ➔ Pull-out Test
• Q30: What is a Non-Destructive Test of Materials?
  Ans: A non-destructive test (NDT) is a method of evaluating the properties of a material without causing damage or failure.
• Q31: Name 4 Non-Destructive Tests for Metals.
  Ans: The 4 non-destructive tests for metals are:

  • ➔ Ultrasonic Testing
  • ➔ Magnetic Particle Testing
  • ➔ Dye Penetrant Testing
  • ➔ Radiographic (X-ray) Testing
• Q32: Name 4 Non-Destructive Tests for Concrete.
  Ans: The 4 non-destructive tests for concrete are:

  • ➔ Rebound Hammer Test
  • ➔ Ultrasonic Pulse Velocity Test
  • ➔ Penetration Resistance Test
  • ➔ Pull-out Test
• Q33: What is a Creep Test?
  Ans: A creep test measures the slow, permanent deformation of a material under constant load and temperature over a long period.
• Q34: What is an Impact Test?
  Ans: An impact test measures the material's ability to resist sudden loads or shocks, usually using Charpy or Izod methods.
• Q35: What is a Fatigue Test?
  Ans: A fatigue test evaluates a material's behavior under repeated cyclic loading to determine its fatigue life.
• Q36: What is a Torsion Test?
  Ans: A torsion test measures the material’s strength and deformation behavior when subjected to twisting or torque.
• Q37: What is a Shear Test?
  Ans: A shear test determines the shear strength of a material by applying forces parallel to its cross-section until failure occurs.
• Q38: What is a Bending Test?
  Ans: A bending test measures the flexural strength and stiffness of a material by applying a load at one or more points until it bends or fractures.
• Q39: State the scope of Bending Test.
  Ans: The bending test is used to:

  • ➔ Determine flexural strength of materials
  • ➔ Study the elasticity and plasticity under bending loads
  • ➔ Evaluate material performance in beams and structural elements
  • ➔ Identify weak points or defects in the material