Strength of Materials: Know Definition, Types of Load, Advantages & Applications

Strength of Materials is applied mechanics that discusses the behaviour of solid bodies for different types of loading and forces that develop due to them inside the body. A thorough concept of mechanical behaviour is important to design structures safely like buildings, bridges, machinery, motors, submarines, and aircraft. Strength of Materials, hence, acts as a key subject in every engineering discipline. The main objective of this analysis is to calculate the stresses, strains, and deflections caused by applied loads in various structures. Both theoretical analysis and experimental data are equally important in investigating the strength of materials. These quantities are evaluated for all load values up to the failure load, providing a complete understanding of the mechanical behaviour of a body.

The response of a structural member to applied forces is governed not only by Newtonian mechanics, which dictates force equilibrium, but also by the mechanical properties of the material from which it is made. In some cases, predicting material behaviour requires laboratory testing to obtain essential data on its characteristics.

In this article, we will explore what strength of materials is, its basics, critical concepts, and practical applications. By the end of this article, you will have a clear understanding of the subject and its relevance in the field of engineering. The information in this article helps you extensively in your SSC JE Mechanical  / RRB JE Mechanical and GATE Mechanical preparation journey.

Also Download Strength of Materials Notes PDF Here !

What is the Definition of Strength of Materials?

To define strength of materials, it is the branch of engineering science that studies the behaviour of solid objects under stress and strain. The objective is to predict material failure and optimize designs for durability and performance.

Key Aspects of Strength of Materials:

• Material Properties: Elasticity, plasticity, toughness, and ductility.
• Structural Behaviour: Analysis of how materials respond to forces.
• Failure Prediction: Understanding fracture, fatigue, and deformation mechanisms.

Loadings refer to the forces or moments acting on a structure. In the strength of materials basics, load types are categorized as follows:

• Tensile Load:
  • Pulling force causing elongation.
  • Example: Ropes and cables in suspension bridges.
• Compressive Load:
  • Pushing force causing shortening.
  • Example: Columns and beams in buildings.
• Shear Load:
  • Parallel forces causing sliding.
  • Example: Scissors cutting paper.
• Torsional Load:
• Twisting force causing angular deformation.
• Example: Drive shafts in vehicles.

Stress Terms

Stress is the internal force per unit area within a material resisting deformation. The key stress terms in strength of materials mechanical engineering include:

• Normal Stress (σ): Occurs perpendicular to the cross-sectional area.

σ=F/A
Where:

• F = Force applied
• A = Cross-sectional area
• Shear Stress (τ): Occurs parallel to the cross-sectional area.

τ=F/A

• Bearing Stress:
  • Stress at the contact surface of two bodies.
  • Stress Parameters for Resistance

Understanding resistance parameters helps in designing materials to endure stress. The primary parameters include:

• Yield Strength: The stress at which a material begins to deform plastically.
• Ultimate Tensile Strength (UTS): Maximum stress a material can endure before failure.
• Factor of Safety (FoS): Ensures designs are safe under maximum expected loads.

Strain Parameters for Resistance

Strain measures deformation relative to the material's original dimensions. The key strain parameters are:

• Normal Strain (ϵ): Change in length per unit length.
  • ΔL = Change in length
  • L0= Original length
• Shear Strain (γ): Angular distortion due to shear stress.

The relationship between stress and strain provides insight into material behaviour.

1.Elastic Region:

• Material returns to its original shape after load removal.
• Governed by Hooke's Law:

σ=E⋅ϵ

Where:

E= Young's Modulus (material stiffness).

2.Plastic Region:

• Permanent deformation occurs beyond the yield point.

3.Fracture Point:

• Material breaks under extreme stress.

Strength of Materials Syllabus for AE/JE Exam

We have covered detailed syllabus in this article, Here's a comprehensive Strength of Materials (SOM) syllabus tailored for AE (Assistant Engineer) / JE (Junior Engineer) Exams:

Strength of Materials Notes for AE/JE Exam
S.N.	Topics
1.	Properties of Materials
2.	Simple Stress-strain and Elastic Constants
3.	Shear Force and Bending Moment
4.	Centroids and Moments of Inertia
5.	Bending Stress in Beams
6.	Shear Stress in Beams
7.	Principal Stress-Strain and Theories of Failure
8.	Torsion of Shafts
9.	Deflection of Beams
10.	Pressure Vessels
11.	Theory of Springs
12.	Theory of Columns
13.	Shear Centre

Advantages of Strength of Materials

The research in SOM is replete with advantages, especially in engineering and design:

• Improved Safety: Renders structures capable of resisting anticipated loads.
• Cost Effectiveness: Maximizes the use of materials and minimizes wastage.
• Longevity: Enhances the life of components and structures.
• Versatility: Can be used in various industries such as automotive, aerospace, and construction.

Applications of Strength of Materials

Strength of materials is highly relevant to the following fields:

• Automotive Industry: Designing chassis, engines, and suspension systems to resist stress.
• Aerospace Industry: Lightweight yet robust materials for aircraft structures.
• Construction and Civil Engineering: A study of beams, columns, and foundations to maintain stability.
• Manufacturing: Developing tools and machines capable of withstanding operational loads.

Stress and Strain Comparison

Property	Definition	Units
Stress (σ)	Internal force per unit area	Pascal (Pa)
Strain (ϵ)	Deformation relative to original dimensions	Dimensionless (ratio)
Young’s Modulus (E)	Stiffness of material	Pascal (Pa)

Conclusion

For AE/JE and government job aspirants, strength of material notes is an essential study resource. Understanding concepts such as stress-strain relations, load types, and material behaviour is essential for solving numerical problems and theoretical questions.

This article concludes all the information related to strength of materials (SOM), which helps to propel your preparation for various AE/JE examinations. To boost your preparation, you should test yourself through a series of Mock Tests for Mechanical Engineering Exams. You can check the syllabus for the AE/JE exam. You can visit the Testbook app to keep yourself updated with all the exam-oriented information related to the upcoming examinations, including GATE Mechanical , RRB ME, ESE, and state AE/JE Mechanical exam.