Mechanical Engineering Concepts And Terminology

mechanical engineering

Mechanical engineering is one of the oldest and broadest disciplines that combines engineering physics and mathematical principles with materials science. It involves the design, analysis, manufacture and maintenance of mechanical systems.

The fundamentals of mechanical engineering go back thousands of years, emerging as a field during the Industrial Revolution in Europe. It continued to evolve and, today, mechanical engineers are involved in areas such as composites, mechatronics, and nanotechnology.

We take a look at what the mechanical engineering field has to offer and explore some of the concepts and terminology mechanical engineers should know.

What Areas Do Mechanical Engineers Work In?

Mechanical engineers are responsible for research, design, development, building and testing mechanical and thermal devices like engines, tools and machines. Among others, mechanical engineering actually overlaps with several other areas including:

  • aerospace engineering
  • metallurgical engineering
  • civil engineering
  • electrical engineering
  • manufacturing engineering
  • chemical engineering
  • industrial engineering

Many are also working in the field of biomedical engineering with a focus on biomechanics, transport phenomena, biomechatronics, bionanotechnology and the modelling of biological systems.

What Does Mechanical Engineering Entail?

Put plainly, mechanical engineers design and oversee the manufacturing of all sort of products ranging from medical devices, batteries and internal combustion engines to elevators and conveyor systems. The field is broad and while it’s a tough graduate market, degree-level mechanical engineers are in a good position.

Typically, their core duties and responsibilities are as follows:

  • Analyse potential issues and identify how mechanical or thermal devices could resolve the problem
  • Design or redesign mechanical and thermal devices (through analysis and CAD or computer-aided design)
  • Develop and test prototypes of devices
  • Analyse test results and change the design if required
  • Oversee the entire manufacturing process of the said device

Like other engineers, mechanical engineers use computers to create and analyse product designs. They also use these systems to run simulations to test how their machine or device will work.

Understanding Mechanical Engineering Concepts

Mechanical engineering is one of the most in-demand skillsets for new graduates. There are certain principles that every mechanical engineer must know if they want to succeed in this career path. Here are some of the most important mechanical engineering concepts you should know.

Clearances and Tolerances

When designing complex and precise components, clearances and tolerances are absolutely essential. In engineering terms, tolerance can be defined as the “permissible limit or limits of variation of a part”. So what exactly does that mean?

Tolerance is vital when ordering parts like nuts and bolts or when you want to determine the most appropriate manufacturing process to create your design. Some precision engineering machines have a maximum tolerance and if you need a tighter tolerance, you need to use a different machine.

In terms of clearances, it directly relates to tolerances as you might have to maintain a clearance of 3 cm + or – 2 cm. The clearance requirement is often in place to avoid friction or stop a component from catching another moving part.

Force, Pressure and Friction

In technical terms, ‘force’ = ‘the measure of mass’ x ‘acceleration’. Friction and pressure are types of forces with friction being the reason everything works the way it does. Friction is the resisting force that is exerted on an object when coming into contact with another object.

Then there is kinetic and static friction where each usually has a different coefficient for a given surface. Friction can be variable based on surface properties, velocities and accelerations.

Pressure is similar to friction as it involves continuous force being exerted against an object when it’s in contact with something else. Pressure is also given as a force on an area such as pounds per square foot (psi).

Velocity and Acceleration

Velocity can be described as “the speed of an object in a given direction”. It is generally a vector of sorts as it has a numerical speed and directional value.

Acceleration, however, “is the change in velocity in a given time”. Looking at the physics side of things, there can be positive and negative acceleration where the negative is often called deceleration.

Understanding velocity and acceleration form the foundation of being an engineer. Every other principle depends on your understanding of these vital mechanical engineering concepts.

Work and Energy

The term ‘work’ stems directly from the principles of force. In simple terms, if you perform work on an object, force is applied to move it over a certain distance or in a specific direction. Energy, on the other hand, is the capacity of doing the work.

For example, when you are at the top of a roller coaster you have a certain amount of energy. This is seen as the potential to drop down the track to gain speed. As you begin to drop toward the ground, your potential (or energy) decreases as the force of gravity starts doing ‘work’ on you.

An analogy that many have used is looking at energy as the currency to do work. Energy and work aren’t difficult principles to grasp especially if you understand forces and accelerations. However, like everything in physics, it builds on your understanding of all the previous principles.

Stress and Strain

“Stress is the force per unit area while strain is the deviation or change in shape as a result of the stress”.

Another simple analogy to help understand these concepts is looking at stress as the number of exams you have when at University while strain is how little time you have in your schedule to study for it.

Stress and strain are especially important in material sciences as their values change for different materials. This is often referred to as maximum stress and strain for a specific material. When you exceed these maximum values, part failure or deformation can easily occur.

Final Thoughts On Mechanical Engineering

All of these concepts are physical in nature and involve a considerable amount of math. Ask any mechanical engineer and they’ll tell you that they use these principles on a daily basis. That said, it’s not always in the same way you would use them in a physics class at college or University.

Most CAD programs and other tools simplify all the calculations as they can determine the values automatically. While technology is there to help, it doesn’t mean you don’t have to understand these all-important mechanical engineering principles.

Get in touch with our team of expert engineers if you need help with a manufacturing project of any shape or size. PRV Engineering can manufacture products in all materials from the most basic mild steels to the more exotic Monel, Inconel, Hastelloy and Titanium.

References

‘https://interestingengineering.com/concepts-mechanical-engineers-need-to-understand’
‘https://en.wikipedia.org/wiki/Mechanical_engineering’
‘https://www.bls.gov/ooh/architecture-and-engineering/mobile/mechanical-engineers.htm’