Performing mechanical and structural inspections is essential to prevent component failure. Structural Engineers inspect structures, plants and equipment using a range of tools and techniques. Stress analysis identifies the different forces and stresses that may be acting on each part of the assembly. Pinpointing such areas allows the engineer to deal with them accordingly.
To carry out a detailed stress analysis, the Finite Element Method (FEM) or finite element analysis (FEA) is used. Also, structural integrity can be verified through fatigue analysis, accelerated durability testing, and FEM using a high-functioning computing system.
In this article, we will explore the basics of stress analysis and why it is vital in mechanical and structural engineering.
What is stress analysis in mechanical engineering?
Mechanical engineering is designing and manufacturing a product using engineering principles and skills to solve problems.
Engineers must think carefully about how different machine parts will work together and under what conditions. Any part of a machine should be strong enough to withstand the stresses of its environment. They need to be durable and resistant to damage.
Stress analysis is one way (in theory) to figure out if a part will fail. Failure can happen as a rupture, deformation, cracking, wear, or fatigue failure. So, stress analysis is an essential tool for design engineers and a must-have for mechanical engineers.
The Basics of Stress Analysis
Every component in a mechanical or structural system is loaded in some way due to applied forces or motion. The response and resistance of the component to these loads will be determined by its mechanical qualities.
In engineering, stress can be simply explained as the force of resistance offered by a body against deformation per unit area. Mathematically, P =F/A, where P is the stress, F is the internal resisting force, and A is the cross-sectional area. On the other hand, strain is defined as the ratio of change in length to the original length when a body is subjected to an external force (Strain= change in length/the original length).
Generally, stress-strain analysis is a primary responsibility for Mechanical and Structural Engineers as they are involved in the design of machines and structures of various sizes, such as mechanical parts and systems, machine tools, buildings, plants and many more. Stress analysis is also used in the maintenance of these structures as well as the investigation of structural breakdowns.
To carry out stress analysis, the geometrical description of the structure, the properties of the materials used for its pieces, how the parts are linked, and the boundary forces that are predicted to be applied to the structure are to be clearly defined. The results and output data from the analysis are usually a quantitative description of how the applied forces vary throughout the structure, resulting in stresses, strains, and deflections of the total structure as well as each individual component.
Stress-strain analysis is frequently used as a tool rather than the main goal, though its ultimate goal is to design components and systems that can sustain a particular load while meeting some optimality requirements.
What are the five types of mechanical stress?
Shear, tension, compression, bending, and torsion are the five types of mechanical stress.
The amount of mechanical stress on a body is a quantity. It happens because of the forces and moments acting on the body. The bigger the forces, the harder it is for a part to fight against them until it breaks.
Since types of stresses are often combined, engineers use methods to determine how much each type adds to the effective stress level and by reversing those effects through mechanical, structural, or hydraulic methods increase the longevity of the product.
Importance of Stress Analysis and why it matters
Preventing Mechanical Failures
There are many reasons why structural failures occur, but often these are caused by poor or inadequate stress analysis.
Mechanical and Structural Engineers are well-versed in FEM and other stress analysis techniques. They provide load conditions, tensile stress and shear stress using high-functioning computing systems. They also create mathematical models, 3d models, and a visible distribution of stress on component parts and assemblies. In this way, a part of the assembly lacking the ability to withstand the expected stress can be identified and rectified, thereby preventing failure across the whole structure.
It may sound quite simple as we describe stress analysis as if it were a straightforward process. However, it is much more complicated and a much lengthier procedure than it may sound.
Established in 2011, Trevilla Engineering performs non-contact 3D inspection and scanning services. Our engineers inspect your assemblies and parts using handheld scanners. This state-of-the-art method is quicker, more efficient, and precise than other modern engineering inspection procedures.
Adding Value to Mechanical Design
Mechanical Engineers can add value during mechanical design by performing stress analysis of the structure, component, or machine before it is completed. Stress analysis leads to a better product or part, building confidence and trust. Stress analysis can result in a better product in terms of design and better stress-withstanding capabilities. Adding value to a product is sometimes referred to as value engineering.
Material selection is also vital to ensuring the durability of a product. Mechanical Engineers have a great deal of knowledge in materials and some metallurgy parts, their disabilities, elasticities, toughness, and strengths. As such, Mechanical Engineers can help select the best materials, components, structures, and vessels for your projects.
Loss Prevention and Safety Factors
Safety is crucial in every industry, sector, or company. Stress analysis is essential to preventing accidents and incidents involving the failure of critical infrastructure. Similarly, poor vibration analysis, stress analysis, and mechanical inspections might lead your plants or machines to collapse, causing injuries or even fatalities.
As a result, it is critical to analyse stresses to determine the maximum allowable normal and shear stresses occurring on the element. This will make it possible for Engineers to comprehend the likely failure mechanism of the materials and then lay down rules to prevent it.
You need to follow the instructions of relevant professionals and follow all the safety procedures and precautions when on-site or in the field. Mechanical inspections and other prerequisites are required to genuinely make a site safe.
Stress analysis can check the integrity of a vessel, machine, or component. This type of essential stress analysis checks how much load a structure can hold per unit area. Proper stress analysis can prevent material and capital losses.
How does FEA calculate stress?
Even though it is easier to figure out stress by hand for simple shapes like beams, industrial applications need much more complicated equations and mathematics. It becomes impossible or time-consuming to figure out the stress by hand. Therefore, FEA methods are used.
With the Finite Element Method and a computer, Finite Element Analysis (FEA) simulates the conditions of a part. FEA programs break up the whole body into many small pieces (called “meshes”) and then use partial differential equations, methodology, and standards to figure out how much stress there is.
On the other hand, FEA analysis only gives an estimate (theory), so postprocessing is very important to get the right solution. And processing the analysis results is just as important as getting them because results are meaningless if you can’t learn from them.
Conclusion
Since the introduction of technology, performing stress analysis on parts and equipment has become much simpler.
Fortunately, today we have high-performing computer systems that help us do most mathematics, calculations, and engineering simulations. For stress analysis and FEM, software like Ansys and Autodesk are widely used. Apart from software and computer systems, physical techniques and machines are also used for initial and final inspections.
Equipped with the latest tools and technology, Trevilla Engineering has proven to be one of the most respected companies in the inspection and risk analysis sector. Access to modern technology has made our experts capable and adept in the areas of manufacturing, design and mechanical inspection procedures.
