Introduction to Engineering Mechanics

The use of mechanics to address issues involving typical engineering components is known as engineering mechanics.

This engineering mechanics course seeks to familiarize students with mechanical issues as they are applied to relevant real-world situations. For students to develop an inductive grasp of the underlying concepts at play, problems of certain sorts are addressed in detail. Students should subsequently be able to identify difficulties of this type in real-world settings and respond accordingly.

Engineering mechanics, which explains how things move and the forces that cause these motions, is the fundamental branch of engineering.

Engineering mechanics examines the forces at equilibrium as well as the stresses and deformations that arise in the components. A component is built based on properties like strength, allowable stresses, or deformations by comparing the applied stress with the component's stress tolerance.

To achieve this, a component's stress must be lower than its stress tolerance.

Engineering mechanics offers essential mathematical techniques for producing engineering designs, together with the core fields of materials science and machine components. Therefore, engineering mechanics should be viewed as a link between theoretical understanding and real-world application, without which it would be impossible to comprehend and thoroughly analyze complicated technological systems.

Differentiating between the many physics branches

As you can see from the graphic, mechanics is the earliest and most basic field of physics. It includes Statics, Dynamics (= Kinematics + Kinetics), Thermodynamics, and Electricity, all of which are extremely useful in engineering. However, the most crucial aspect of them is statics (the study of a body at rest), which not only serves as the foundation for all others but also has the greatest technical relevance. Physics also includes the theories of optics, waves, quantum mechanics, and relativity, none of which have any enduring applications in engineering.

Differentiating between traditional and contemporary physics

Classical physics refers to the antiquated physics theories that are frequently employed to describe the states of physical phenomena on a macroscopic scale, such as the rules guiding the motion of masses that are typically larger than atoms and molecules. On the other hand, modern physics is concerned with the more recent ideas that explain physical events.

Quantum physics and relativity are two major subfields of contemporary physics. These contemporary hypotheses came to light because of investigations into the nature of matter at far more microscopic and abstract levels. As a result, ideas from the classical school of physics are frequently thought to have been developed before 1900, whereas theories from the contemporary school date from the 20th and 21st centuries.

Statics

With the aid of Newton's second rule of motion, we can explain how bodies move.

Force = Mass*Acceleration

When a body is at rest or moving at a constant speed, its acceleration (a) is zero, which is the case in statics. Therefore, the total force acting on a body at rest or moving at a constant speed must be zero. To put it another way, the total of the forces acting on the body must be zero.

Sum of Forces = 0

Free body diagram: a resource for comprehension and problem-solving

To depict all forces acting on a body at rest, engineers frequently create what is known as a "free body diagram". To satisfy the static constraint of no acceleration present, these forces are next decomposed into vectors consistent with a meaningful coordinate system and added in sets (components parallel to each basis vector). These sets are then set to zero.

Typically, this leads to sets of equations that are easily solved using simple methods from linear algebra or even just basic algebra and substitution.

Example of Free body diagram:

Truss

There are no shear or moment forces; instead, forces act along with the members. Therefore, a system made completely of two-force members that can only support axial loads is referred to as a truss. Truss ends are fastened to prevent moments from passing through them. Forces are the only responses at a truss member's ends.

Trusses only experience external forces at their end points. Both the method of sections and the method of joints can be used to solve truss problems. In the method of sections, a fictitious cut is made through the member(s) of interest, and the forces and moments in the member(s) are determined using the global equilibrium of forces and moments.

In the method of joints, a single joint is isolated and analyzed, and the resulting forces (which are not always given a numerical value) are transferred to adjacent joints, where the process is repeated. After that, the set of equations can be resolved using substitution or linear algebra.

Dynamics

Dynamic simply implies that when a force is applied to an item, it moves with a certain amount of speed. For instance, a car is going at some velocity down the road.

While dynamics deals with structures or things that have a non-zero acceleration, statics deals with the portion of mechanics when all objects are motionless.

Kinematics and kinetics are two subfields of dynamics. Without considering the forces at play, kinematics deals only with displacement, velocities, and accelerations. Kinetics is the study of the forces and moments that cause a body to move, as well as the measurement of numerous characteristics that describe the motion.

Dynamics is a division of mechanics that focuses on the investigation of moving objects.

Divisions of dynamics

Kinematics and kinetics are the two subfields of dynamics.

A subfield of mechanics known as kinematics discusses how a particle or body moves without applying force.

A subfield of mechanics known as kinetics combines the force applied on an object with its mass and rate of acceleration.

Signs and symbols

S = distance.

If x is moved horizontally, y is moved vertically.

v = velocity, and vf = final velocity.

starting velocity is vi.

a = acceleration, and g = gravitational acceleration.

t = time

Engineering mechanics is often broken down into the following subdisciplines at academic institutions:

• Engineering mechanics I, using a statics-focused approach
• Engineering mechanics II, with a focus on electrostatics and material strength
• Engineering mechanics III, Kinematics and kinetics (dynamics) in engineering mechanics

Force

Any action that seeks to alter the resting or moving condition of a body to which it is applied may be referred to as force.

The three elements that make up a comprehensive definition of force are referred to as its specification or characteristics. Thus, a force's qualities are as follows:

1. Dimension
2. Application Point
3. The way it should be used

Line of action of force

A force's direction is the way it tends to move a body when it is applied, measured along a straight line through its point of application. The force line is the name given to this path.

Composition of two forces

The issue of composition of forces is the process of reducing a given system of forces to the simplest system that will serve as its equivalent.

Law of parallelograms

If a body at point A is subjected to two forces represented by the vectors AB and AC operating at an angle of. Their combined action is like that of a single force, symbolized by the vector AD, which was formed as the diagonal of the parallelogram built using the vectors AB and AC as directed in the figure.

Collinear force equilibrium

Law of equilibrium: For two forces to be in equilibrium, they must all be acting in directions that are opposing, collinear, and of equal size.

Resolution of a force

The issue of resolution of a force is the replacement of a single force by several components that will be comparable in action to the supplied force.

Equilibrium of collinear forces:

Law of equilibrium: For two forces to be in equilibrium, they must be collinear in action, equal in size, and moving in opposing directions.

Engineering mechanics subject areas

Statics

Lessons in statics include the fundamentals of assessing loads on mechanical systems. This information serves as the foundation for developing and sizing machine parts and component parts.

Strength of materials

Strength of materials is concerned with determining the stress states that emerge from the deformation of elastic systems under loads such as pressure, tension, bending, torsion, and shearing.

Dynamics (kinematics and kinetics)

Dynamics studies dynamic systems. Kinematics deals with motion patterns rather than focusing on the origin of motion. Kinetics examines how stiff bodies move when forces are applied.

Machine dynamics

Machine dynamics examines how dynamic forces and motion factors interact in machines, building on the foundations of engineering mechanics.