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Mechanical Design – Principles, Theories, Software


A mechanical designer.
Image Source: Flickr.

Mechanical design is a very interesting and very professional area in engineering. If a company makes physical things such as automobiles, phones, etc. they are performing mechanical design in their R&D departments. 

But every time, even the biggest corporations could not come up with the best ones for their products. Remember the tools of cars that are not user-friendly(I will not give a specific brand…). 

Here, we explained the general aspects of mechanical design around these topics; 

  • What is mechanical design? 
  • How do obtain a good design? 
  • What is the place of software in this field? 
  • What are the general theories in the mechanical design?
  • FAQs. 

Professional Mechanical Design

Gears in mechanical design.

Mechanical design is a field where we design useful physical stuff in terms of the engineering approach. One can design parts and things by using some computer software but not all the designs include an engineering approach. 

Professional engineers are designing the professional products. Sometimes people confuse the external or visual design with this. But in mechanical design, the usefulness and the cost/performance of the designed product are important. 

How to Obtain Good Mechanical Designs?

The short way to obtain good designs depends on the use of an engineering approach. Engineering is the art of optimization and we can use professionally to obtain good designs. Various engineering tools we can use in the engineering design of systems. The ability to use engineering tools also requires an engineering approach. Among the engineering tools in design; 

  • Reliable sources that designers can get help from them while performing a professional design. 
  • We use computer-aided design software to design 3D models of mechanically designed things or systems.
  • Also we use computer-aided engineering tools and software to model the theoretically designed engineering systems. 
  • Engineering economics to calculate the ability to compete with the mechanically designed system. Cost-competitiveness of the designed system is very important. 
  • Manufacturability of the mechanically designed system must obey the standardizations of that system. 

Use of the Engineering Theories

Engineering theories in mechanical design.
Image Source: Rawpixel.

Mechanical design starts with the strict definition of the problem or the system to we design. And they are making the theoretical assumptions. The most important engineering sources in design are; statics, dynamics, the strength of materials, machine elements, fluid mechanics, thermodynamics, and so on. 

For example, the engineering design of a turbine system includes different kinds of engineering disciplines. In the efficiency and performance calculations of the turbine, we use fluid mechanics and thermodynamics. We make the required engineering assumptions for the performance calculations of the turbine system. 

In structural designmachine elementsthe strength of materials, and materials science are the required disciplines. The standard mechanical elements such as shaftsgear systems, and assembly elements are designed and defined according to the mechanical elements. The strength calculations and fatigue calculations of the designed system are the topics of the strength of materials. And the selection of proper materials for the system is related to materials science. 

So, there are lots of engineering calculations and engineering approaches required in the design of a mechanical system. Dealing with these kinds of topics in design is for the professional mechanical design engineers. 

CAD Software in Mechanical Design

Siemens PLM Software(Image Source: Flickr.).

Visualization and the illustration of the theoretically designed mechanical system are very important for design. Visually showing and depicting what kind of engineering design that we obtain is an important process and CAD software is generally used in this way. 

There are lots of CAD software that we use in design. This CAD software provides very useful tools to obtain 3D structures and assemblies professionally. Also, the 3D illustration of the dynamics of the designed mechanical system is possible in most CAD software. 

In most the CAD software also, there are various possibilities to obtain the technical drawings of the designed systems. Technical drawings are very important in the manufacturing phase of all the elements and parts of the mechanically designed system. The tools to obtain standard engineering drawings of mechanical systems in CAD software are generally very good. A mechanical designer can use all the required tools of CAD software. 

CAE and FEA Tools in Mechanical Design

CAE in mechanical design.

CAE means computer-aided engineer and FEA means finite element analysis. We use FEA which is a theoretical engineering tool to calculate engineering systems in terms of strength, performance, etc. They generally use FEA theory in most the CAE tools. We can model a mechanical design in CAE software to see how the theoretical designed system will act if the prototype is produced. 

The ability to use CAE tools effectively is very important to obtain realistic models of engineering systems in a computational environment. 

We use other CAE tools for engineering calculations. Sometimes engineering calculations for mechanical design can be very complex and different kinds of computational CAE tools we use in the engineering calculations. In these kinds of CAE tools, we use a type of programming language. They generally code macros and programs for engineering calculations. And, these engineering calculations will be more accurate if we compare to long and burdensome hand calculations. 

Combining the obtained CAE and FEA data with the theoretical calculations in engineering is very important to obtain accurate calculations for designs. 

Engineering Economics and Optimization

The design approach deals with the design of the most optimum engineering system. Here, two important factors we consider; safety and cost. The optimization between safe design and cost-competitive design is the most important task of design. We can obtain the safest design by using excessive materials with excessive safety precautions. But this means cost. We can also obtain the cheapest mechanical design. But safety will be in danger. Also, there will be safety standardizations and regulations of the mechanically designed system. 

In mechanical design, providing a balance between these two edges is very important. Various kinds of engineering economics and engineering approaches we use to provide a balance between safety and cost. 

Manufacturability of the Mechanical Design

Yes, we obtained a design but can we produce and manufacture all the parts and elements of the obtained design? It is very important to obtain a mechanical design that can we easily manufacture with the available manufacturing processes. A designer must be aware of the available manufacturing methods to produce the designed parts. 

Also, the cost of manufacturing is another aspect of mechanical design. All the parts that make the design up we should design according to the cheapest manufacturing costs. Because the manufacturing costs of the manufactured part will add a direct cost-up to the system. 

Softwares in Mechanical Design

Computational sources are very important in design. In today’s technology, the use of computers is very common in design. So, we use various software packages. The most common type of software packages is CAD software, CAE software, and FEA software in mechanical design. 

Which CAD Software We Use in Design?

The most common CAD software that they use in design in Solidworks, AutoCAD, CATIA, and Siemens NX around the world. The tools of Solidworks are very simple to use and they are very simple to learn. Because of this, Solidworks is one of the most common CAD software in mechanical design. 

Lots of professional companies are using Siemens NX in the R&D departments. Because there are lots of Siemens systems that they embed into the general manufacturing systems and Siemens NX can be used with these systems. 

CATIA is another good CAD tool in design. They use CATIA generally in the automotive industry and the tools of CATIA are somewhat more advanced than Solidworks. 

They use AutoCAD generally in the technical drawing generation and the tools of AutoCAD 2D are very good in the generation of the professional engineering drawings. 

CAE Softwares in Mechanical Design

In mechanical design, they use different software engineering calculations which we call CAE software. CAE software is very common in all the engineering branches, especially in mechanical design. One of the most used CAE software is Matlab and Mathematica in design. 

In Matlab, they perform all the engineering calculations with the special programming language of Matlab. Also in Simulink, there are tools to design special engineering systems. Mathematica is another important CAE software that they use in the same way as Matlab. 

FEA Software

FEA software is a specially designed software package to perform the finite element analysis of mechanically designed systems. You can create complex realistic mechanical simulations of the designed systems. The simulations are based on finite element methods which is a numerical approach in engineering. 

There is also various FEA software available that we mainly use in mechanical design. The most important one is ANSYS. ANSYS provides various kinds of tools for simulating different static and dynamic mechanical designs. You can check the other FEA software that is generally used in mechanical design from this link.

General Engineering Theories in Design

In mechanical design, we are using engineering theories that are from mechanical engineering in general. Among these engineering theories, the strength of materials and machine elements are the most common ones. 

In the safe design of mechanical systems, we use theories on strength of materials. In the design of structural elements, there are various theories according to the material and use of the systems in the strength of materials discipline. 

We use fluid mechanics and thermodynamics also in the performance calculations of the designed engineering systems. Thermodynamics deals with the total energy that mechanical systems consume and produce. We generally use performance calculations of automobile engines and HVACs in thermodynamics and fluid mechanics. They design systems that include fluid such as turbines, pumps, and compressors according to the fluid mechanic’s theories. 

Engineering systems that are related to thermal applications such as heat exchangers and heaters are also calculated with thermodynamics and heat transfer theories. 

In general, they are using these fundamental engineering theories in the mechanical design of engineering systems. And other additional engineering approaches that engineering design procedures include.


As you understand, design starts with the calculation of engineering theories. In these calculations, the general limitations and general lines of mechanical design. 

Obtained theoric design of the intended engineering system is illustrated and mechanized in the CAD environments. And if required, we can obtain FEA models of the engineering systems. 

We use CAE tools that are extensively in design activites. They use various optimization tools of CAE programs in mechanical design calculations. 

Also, the total manufacturing costs of the obtained mechanical design are very important. We perform engineering calculations also for the manufacturing of the engineering system. 

Cost competitiveness is also very important in the obtained design. There are probably lots of opponents of the designed system in the market. The designed system must be calculated on an engineering basis to be cost-competitive.

FAQs About Mechanical Design

Why mechanical design is important? 

To obtain useful and professional systems for human society, an engineering approach is required. This engineering approach can be applied in the design of the systems. So, a mechanical design approach must be applied.

Which kinds of companies are making the mechanical design?

There are various kinds of companies that are making mechanical designs if they want to produce commercial products for the market. If a company makes commercial products, this means that the company makes big investments in design. 

Which software is used in mechanical design?

In general, FEA software, CAD software, CAE software, programming languages, and Microsoft Excel are generally used in design. 

What is the mechanical design service?

Companies that are serving design services are generally remote companies that give consultancy to the companies that want to produce commercial products.


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