Understanding Stress and Beams

What is Hooke's Law and how does it relate to stress and strain?

• Hooke's Law describes the relationship between force and velocity in fluids.

• Hooke's Law describes the linear relationship between stress and strain in elastic materials.

• Hooke's Law states that stress is proportional to temperature.

• Hooke's Law applies only to plastic materials and not elastic ones.

Define elastic limit and its significance in material science.

• The elastic limit is the point where a material breaks completely.

• The elastic limit is the maximum stress a material can endure without permanent deformation, significant for material selection and structural integrity.

• The elastic limit refers to the temperature at which a material melts.

• The elastic limit is the minimum stress required to cause a material to fracture.

What are the different types of elastic constants?

• Young's modulus, shear modulus, bulk modulus.

• Tensile strength, compressive strength, flexural strength

• Thermal conductivity, electrical conductivity, magnetic permeability

• Viscosity, surface tension, density

Explain the relationship between Young's modulus, shear modulus, and bulk modulus.

• Young's modulus only applies to tensile stress.

• Shear modulus is unrelated to material elasticity.

• Bulk modulus measures thermal conductivity.

• Young's modulus, shear modulus, and bulk modulus are interrelated measures of material elasticity, defined through Poisson's ratio.

What is the formula for calculating stress?

• Stress = Area / Force

• Stress = Force + Area

• Stress = Force / Area

• Stress = Force * Area

Describe the stress-strain curve and its key features.

• The stress-strain curve illustrates the relationship between stress and strain in materials, featuring key regions such as elastic, yield, plastic, ultimate tensile strength, and fracture.

• It represents the temperature change in materials under stress.

• The curve is irrelevant in material science and engineering.

• The stress-strain curve only shows the elastic region of materials.

What is the difference between simple and compound bars?

• Simple bars are more expensive than compound bars.

• Simple bars are always longer than compound bars.

• The difference is that simple bars consist of one material, whereas compound bars are made from multiple materials.

• Compound bars are made from a single material only.

How does thermal stress occur in materials?

• Thermal stress is caused by moisture absorption in materials.

• Thermal stress occurs due to constrained expansion or contraction of a material when its temperature changes.

• Thermal stress results from the application of external forces on a material.

• Thermal stress occurs only in metals during welding processes.

What are principal stresses and how are they determined?

• Principal stresses are only found in fluids.

• Principal stresses are always equal in all directions.

• Principal stresses can be determined solely by visual inspection.

• Principal stresses are the maximum and minimum normal stresses at a point in a material, determined through stress transformation equations or Mohr's circle.

Define principal planes and their importance in stress analysis.

• Principal planes are orientations of maximum and minimum normal stress with zero shear stress, crucial for simplifying stress analysis.

• Principal planes indicate the direction of maximum shear stress.

• Principal planes are the same as shear planes in stress analysis.

• Principal planes are irrelevant in determining material failure.