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Questions and Answers
Which term describes the study of materials that relate stress to strain?
Which term describes the study of materials that relate stress to strain?
What behavior do most materials exhibit under stress according to Hooke’s Law?
What behavior do most materials exhibit under stress according to Hooke’s Law?
Which of the following expresses the concept that no real material behaves as perfectly elastic or perfectly plastic?
Which of the following expresses the concept that no real material behaves as perfectly elastic or perfectly plastic?
What property is generally used to describe inelasticity in materials?
What property is generally used to describe inelasticity in materials?
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Which term refers specifically to the resistance of a fluid to flow?
Which term refers specifically to the resistance of a fluid to flow?
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In which year was Hooke’s Law of elasticity discovered?
In which year was Hooke’s Law of elasticity discovered?
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Which term best describes the flow and deformation aspects of materials under applied stress?
Which term best describes the flow and deformation aspects of materials under applied stress?
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What does not accurately describe the behavior of real materials during deformation?
What does not accurately describe the behavior of real materials during deformation?
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Which of the following terms describes a material's property to withstand deformation without breaking when a compressive force is applied?
Which of the following terms describes a material's property to withstand deformation without breaking when a compressive force is applied?
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What property of a material is defined by its ability to return to its original shape after the removal of a force?
What property of a material is defined by its ability to return to its original shape after the removal of a force?
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Which mechanical property refers to the ability of a material to absorb energy during deformation before fracturing?
Which mechanical property refers to the ability of a material to absorb energy during deformation before fracturing?
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How is plasticity best described in the context of material properties?
How is plasticity best described in the context of material properties?
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Which of the following properties is concerned with the behavior of materials when immersed in a fluid?
Which of the following properties is concerned with the behavior of materials when immersed in a fluid?
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What does the term 'flexural strength' refer to in mechanical properties?
What does the term 'flexural strength' refer to in mechanical properties?
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Which of the following properties describes a material's tendency to expand when heated?
Which of the following properties describes a material's tendency to expand when heated?
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What characterizes Hookean behavior in materials under small deformations?
What characterizes Hookean behavior in materials under small deformations?
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Which term describes the behavior of a material transitioning from elastic to plastic behavior?
Which term describes the behavior of a material transitioning from elastic to plastic behavior?
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Which type of strain is defined as recoverable after the load is removed?
Which type of strain is defined as recoverable after the load is removed?
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What does dilatational stress primarily affect?
What does dilatational stress primarily affect?
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How is the degree of plasticity defined in materials under loading?
How is the degree of plasticity defined in materials under loading?
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Which modulus is specifically associated with the resistance of a material to shear deformation?
Which modulus is specifically associated with the resistance of a material to shear deformation?
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What distinguishes plastic strain from elastic strain?
What distinguishes plastic strain from elastic strain?
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What is the result of deviatoric stress on a material?
What is the result of deviatoric stress on a material?
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Which of the following best defines the concept of stress in materials?
Which of the following best defines the concept of stress in materials?
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What occurs at the bioyield point of a solid material?
What occurs at the bioyield point of a solid material?
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How does stress-relaxation behavior manifest in a material over time?
How does stress-relaxation behavior manifest in a material over time?
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Which of the following tests is designed to study the viscoelastic behavior of materials?
Which of the following tests is designed to study the viscoelastic behavior of materials?
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In a creep test applied to biological materials, what phenomenon is observed?
In a creep test applied to biological materials, what phenomenon is observed?
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Which characteristic distinguishes viscoelastic materials from purely elastic materials?
Which characteristic distinguishes viscoelastic materials from purely elastic materials?
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What is the result of the recoil phenomenon in viscoelastic behavior?
What is the result of the recoil phenomenon in viscoelastic behavior?
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In the context of mechanical testing, what does the Weissenberg effect indicate?
In the context of mechanical testing, what does the Weissenberg effect indicate?
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Which statement accurately describes Poisson’s Ratio (µ) in materials science?
Which statement accurately describes Poisson’s Ratio (µ) in materials science?
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Which model describes a fluid that behaves like a solid until a certain stress threshold is exceeded?
Which model describes a fluid that behaves like a solid until a certain stress threshold is exceeded?
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What is the primary characteristic of a pseudoplastic fluid?
What is the primary characteristic of a pseudoplastic fluid?
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What property defines viscosity in the context of fluid dynamics?
What property defines viscosity in the context of fluid dynamics?
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Which combination model includes elements of both viscous and elastic behavior?
Which combination model includes elements of both viscous and elastic behavior?
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When referring to Newton's Law of Viscosity, what is the proportionality constant that relates shear stress to the velocity gradient?
When referring to Newton's Law of Viscosity, what is the proportionality constant that relates shear stress to the velocity gradient?
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In which scenario would a dilatant fluid be expected to behave uniquely?
In which scenario would a dilatant fluid be expected to behave uniquely?
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Which of the following tests is specifically used to observe the time-dependent deformation of materials?
Which of the following tests is specifically used to observe the time-dependent deformation of materials?
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What characteristic is NOT associated with a viscous (dashpot) model?
What characteristic is NOT associated with a viscous (dashpot) model?
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Study Notes
Mechanical Properties
- Mechanical properties describe how materials change shape and size when forces are applied.
- These properties include Hardness, Compressive strength, Tensile strength, Impact resistance, Flexural strength, Sliding coefficients of friction, Coefficient of expansion, Elasticity, Plasticity, Aerodynamic properties, and Hydrodynamic properties.
Hardness
- Hardness measures a material's resistance to indentation.
- A carbide ball (indenter) is pressed into the specimen surface under a known force.
- The indentation depth is measured and used to determine hardness.
Compressive Strength
- Compressive strength is the material's ability to resist a force pushing inwards.
- A sample is placed between two plates.
- The axial force required to compress the specimen to failure is measured.
Tensile Strength
- Tensile strength is the material's ability to resist a pulling force.
- A test specimen is held in grips of a universal testing machine.
- The force required to pull the specimen until failure is measured.
Impact Resistance
- Impact resistance measures a material's ability to absorb impact energy.
- Methods include dropping a weight onto the sample to measure the energy absorbed.
Flexural Strength
- Flexural strength is a test related to bending.
- The sample is supported at the ends and subjected to a compressive or tensile force.
Sliding Coefficients of Friction
- The sliding coefficient of friction is the measure of friction between two surfaces.
Coefficient of Expansion
- This property refers to how much the size of a material changes with temperature.
Elasticity
- Elasticity is a material's ability to recover its original shape after deformation by an applied force.
Plasticity
- Plasticity is the material's ability to undergo permanent deformation when forces are applied.
Aerodynamic Properties
- Aerodynamic properties describe how a material behaves in air or other gaseous fluids when exposed to moving gas.
- This considers forces acting on the material and includes terminal velocity and aerodynamic drag.
Hydrodynamic Properties
- Hydrodynamic properties explain a material's behavior in fluids when exposed to the motion of the fluid and the consequent forces.
- This includes drag force and terminal velocity, along with viscosity and kinematic viscosity.
Rheological Properties
- Rheological properties explain how a material flows and deforms under applied stress.
- This involves both flow and deformation behavior.
Rheology
- Rheology is the study of the relationship between stress and strain in materials.
- It also includes the branch of mechanical properties of materials that have both solid-like and liquid-like characteristics.
Deformation of Materials
- Materials deform in response to stress.
- Types of deformation include Elastic (Hookean, Non-Hookean), Inelastic deformations (viscoelastic and viscoplastic).
- Hooke's law states the displacement of an object is directly proportional to the force.
Hooke's Law
- A direct proportionality relationship between the displacement of an object and the applied force, for small deformations under tensile or compressive loads.
Viscosity
- Viscosity measures a fluid's resistance to flow.
Flow of Materials
- Materials flow under stress, classified as plastic, viscous (Newtonian and non-Newtonian), Bingham, and Pseudoplastic.
Newton's Law of Viscosity
- The force required to maintain motion of a fluid's lower plate is proportional to the velocity gradient.
Tests for Viscoelastic Behavior
- Methods used to study viscoelastic behavior include Stress-relaxation, Creep, and Oscillatory (Dynamic) tests.
Stress-Relaxation and Creep Tests
- Stress-relaxation tests involve deforming a material to a constant strain, measuring how the stress necessary to maintain the strain decreases over time.
- Creep tests demonstrate how a material continuously deforms under a constant stress over time.
Stress-Relaxation Test
- Under constant strain, the stress required to maintain the strain decreases with time.
Creep Test
- Under constant load, biological materials continue to deform with time.
Oscillatory (Dynamic) Test
- This method involves cyclic loading and unloading of the sample, used to study viscoelastic behavior.
Mechanical Models of Viscoelastic Behavior
- Spring, Dashpot, Maxwell, Kelvin-Voigt, and Burger models provide mechanical representations of viscoelastic material behavior.
Capillary Flow Viscometer, Orifice Type Viscometer, Falling Ball Viscometer, Rotational Viscometers (single-spindle, coaxial cyliners, cone-and-plate, parallel-plate), Vibrational (Oscillation) Viscometer, Bostwick Consistometer
- Various instruments used to measure viscosity.
Dilatational vs. Deviatoric Stress and Strain
- Dilatational stress/strain causes changes in volume.
- Deviatoric stress/strain involves changes in shape, with negligible volume changes.
Thixotropic and Rheopectic Behavior
- Thixotropy is a time-dependent property where viscosity decreases with shearing and increases when the shearing stops.
- Rheopexy involves viscosity increasing with shearing.
Other Types of Viscometers
- A variety of instruments are used to measure viscosity.
What about blood?
- Blood's rheological behavior is a complex characteristic, depending on the applied force.
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Description
This quiz covers the mechanical properties of materials, including hardness, compressive strength, tensile strength, and more. Test your understanding of how these properties influence material performance and behavior under various forces. Ideal for students studying materials science or engineering.
