Mechanics of Materials and Material Properties Flashcards
Refresh concepts for the FE Mechanical Exam
Front (Question)
Back (Answer)
What are the main types of beams considered in shear and moment diagrams?
Common types include simply supported, fixed, and cantilever beams.
How does Mohr’s circle assist in failure analysis?
Mohr’s circle helps visualize and calculate principal stresses and their orientations, critical in assessing stress conditions that may lead to failure.
Describe the effects of axial loads on material properties.
Axial loads cause normal stress and strain, potentially altering mechanical properties such as stiffness and ductility.
What is the significance of the neutral axis in bending?
The neutral axis is the fiber in beam sections that experiences no stress during bending.
How is shear stress distributed in a circular shaft under torsional load?
Shear stress in a circular shaft under torsion is maximum at the surface and zero at the axis.
Define the polar moment of inertia and its relevance to torsional loads.
The polar moment of inertia measures resistance to torsional deformation, critical for shaft design.
Explain how temperature changes cause stress in materials.
Temperature changes can cause expansion or contraction, leading to thermal stress if deformation is constrained.
What is superposition of stresses in combined loading?
Superposition involves adding individual stress components from different loads to determine the total stress state in a member.
How are deformations measured in materials testing?
Deformations can be measured using devices like strain gauges, which monitor changes in material length under load.
What factors affect the buckling of columns?
Factors include the column’s material properties, cross-sectional area, length, and end conditions.
Describe a statically indeterminate system.
A statically indeterminate system has more unknown supports or internal forces than available equilibrium equations.
What are the chemical properties of materials important in engineering?
Chemical properties include reactivity, corrosion resistance, and chemical stability under operational conditions.
How do electrical properties affect material selection?
Electrical properties like conductivity and resistivity determine a material’s suitability for electrical and electronic applications.
What defines mechanical properties of materials?
Mechanical properties include strength, hardness, ductility, and toughness, indicating how materials respond to mechanical forces.
How is thermal conductivity important in material selection?
Thermal conductivity affects a material’s ability to conduct heat, crucial in applications like heat exchangers and thermal insulation.
What is shown in a stress-strain diagram?
It shows the relationship between stress and strain under applied forces, illustrating elastic and plastic behavior.
Differentiate between ferrous and nonferrous metals.
Ferrous metals contain iron, are typically magnetic, and prone to corrosion; nonferrous metals do not contain iron and are more resistant to corrosion.
Why are composites considered engineered materials?
Composites are engineered for specific properties, combining two or more materials to achieve performance not possible with individual components.
List some common manufacturing processes.
Common processes include casting, forging, machining, and joining.
What is the significance of phase diagrams in materials science?
Phase diagrams show the stable phases of a material under different conditions of temperature and pressure, guiding heat treatment and alloy design.
How does corrosion control impact material lifespan?
Effective corrosion control extends the lifespan of materials by reducing degradation in aggressive environments.
What are the primary considerations in materials selection?
Considerations include mechanical properties, cost, availability, environmental impact, and compatibility with other materials.
How is fatigue different from fracture in failure mechanisms?
Fatigue results from cyclic stress, causing progressive structural damage, while fracture is the separation of a body into two or more pieces under stress.
What is creep in materials, and what factors influence it?
Creep is the time-dependent permanent deformation under constant load, influenced by temperature, material type, and time.
Describe the method for constructing shear and moment diagrams.
Constructing diagrams involves calculating shear and moment values at key points along the beam, based on applied loads and support conditions.
How does the axial load affect the stress and strain in a material?
Axial loads cause uniform normal stress across the cross-sectional area, resulting in elongation or compression.
What is the role of Mohr’s circle in stress analysis?
Mohr’s circle provides a graphical method to determine principal stresses, maximum shear stresses, and their orientations.
Explain the role of the bending stress equation in beam design.
The bending stress equation relates the bending moment, material properties, and cross-sectional geometry to calculate the stress in a beam.
What does Mohr’s circle represent in stress analysis?
Mohr’s circle graphically represents the state of stress at a point, showing principal stresses and maximum shear stresses.
How do axial loads affect stress and strain in materials?
Axial loads cause normal stress (compression or tension) and corresponding strain along the axis of the material.
