18 Mechanical Properties Which Every Mechanical Engineer Should Know

Material selection for any product is main part of a manufacturing industries. The quality of product is highly depends upon its material properties. These properties are used to distinguish materials from each other. For Example: A harder material is used to make tools.A ductile material is used to draw wires. So the knowledge of mechanical properties of material is desirable for any mechanical student or for any person belongs to mechanical industries. This article brings top 18 mechanical properties. I hope you will like it.

Mechanical properties of material:

There are mainly two types of materials. First one is metal and other one is non metals. Metals are classified into two types : Ferrous metals and Non-ferrous metals.

Ferrous metals mainly consist iron with comparatively small addition of other materials. It includes iron and its alloy such as cast iron, steel, HSS etc. Ferrous metals are widely used in mechanical industries for its various advantages.

Nonferrous metals contain little or no iron. It includes aluminum, magnesium, copper, zinc etc.

Most Mechanical properties are associated with metals. These are

#1. Strength:

The ability of material to withstand load without failure is known as strength. If a material can bear more load, it means it has more strength. Strength of any material mainly depends on type of loading and deformation before fracture. According to loading types, strength can be classified into three types.

• a. Tensile strength:
• b. Compressive strength:
• 3. Shear strength:

According to the deformation before fracture, strength can be classified into three types.

• a. Elastic strength:
• b. Yield strength:
• c. Ultimate strength:

#2. Homogeneity:

If a material has same properties throughout its geometry, known as homogeneous material and the property is known as homogeneity. It is an ideal situation but practically no material is homogeneous.

#3. Isotropy:

A material which has same elastic properties along its all loading direction known as isotropic material.

#4. Anisotropy:

A material which exhibits different elastic properties in different loading direction known as an-isotropic material.

#5. Elasticity:

If a material regain its original dimension after removal of load, it is known as elastic material and the property by virtue of which it regains its original shape is known as elasticity.

Every material possess some elasticity. It is measure as the ratio of stress to strain under elastic limit.

#6. Plasticity:

The ability of material to undergo some degree of permanent deformation without failure after removal of load is known as plasticity. This property is used for shaping material by metal working. It is mainly depends on temperature and elastic strength of material.

#7. Ductility:

Ductility is a property by virtue of which metal can be drawn into wires. It can also define as a property which permits permanent deformation before fracture under tensile loading. The amount of permanent deformation (measure in percentage elongation) decides either the material is ductile or not.

Percentage elongation = (Final Gauge Length – Original Gauge Length )*100/ Original Gauge Length

If the percentage elongation is greater than 5% in a gauge length 50 mm, the material is ductile and if it less than 5% it is not.

#8. Brittleness:

Brittleness is a property by virtue of which, a material will fail under loading without significant change in dimension. Glass and cast iron are well known brittle materials.

#9. Stiffness:

The ability of material to resist elastic deformation or deflection during loading, known as stiffness.  A material which offers small change in dimension during loading is more stiffer. For example steel is stiffer than aluminum.

#10. Hardness:

The property of a material to resist penetration is known as hardness. It is an ability to resist scratching, abrasion or cutting. 

It is also define as an ability to resist fracture under point loading.

#11. Toughness:

Toughness is defined as an ability to withstand with plastic or elastic deformation without failure. It is defined as the amount of energy absorbed before actual fracture.

#12. Malleability:

A property by virtue of which a metal can flatten into thin sheets, known  as malleability. It is also define as a property which permits plastic deformation under compression loading.

#13. Machinability:

A property by virtue of which a material can be cut easily.

#14. Damping:

The ability of metal to dissipate the energy of vibration or cyclic stress is called damping. Cast iron has good damping property, that’s why most of machines body made by cast iron.

#15. Creep:

The slow and progressive change in dimension of a material under influence of its safe working stress for long time is known as creep. Creep is mainly depend on time and temperature. The maximum amount of stress under which a material withstand during infinite time is known as creep strength.

#16. Resilience:

The amount of energy absorb under elastic limit during loading is called resilience. The maximum amount of the energy absorb under elastic limit is called proof resilience.  

#17. Fatigue Strength:

The failure of a work piece under cyclic load or repeated load below its ultimate limit is known as fatigue. The maximum amount of cyclic load which a work piece can bear for infinite number of cycle is called fatigue strength. Fatigue strength is also depend on work piece shape, geometry, surface finish etc.

#18. Embrittlement:

The loss of ductility of a metal caused by physical or chemical changes, which make it brittle, is called embrittlement.

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Why Tractors have their exhaust system(Silencer) fitted in the front of the vehicle,while other automobiles have their silencer at their back?

1. . You can answer this question .
2. 2. You can like the best answer. 
3. 3. You can share the question.

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TEN PRINCIPLES FOR GOOD MACHINE DESIGN

1. Good design is innovative.
2. Good design makes a product useful.
3. Good design is aesthetic.
4. Good design makes a product understandable.
5. Good design is unobtrusive.
6. Good design is honest.
7. Good design is long-lasting.
8. Good design is thorough down to the last detail.
9. Good design is environmentally friendly.
10. Good design is as little design as possible.

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DIFFERENCE BETWEEN AUTOCAD AND SOLIDWORKS

SolidWorks is what we call a "parametric" solid modeller used for 3-D design. Parametric means that the dimensions can have relationships between one another and can be changed at any point during the design process to automatically alter the solid part and any related documentation (blueprint). AutoCAD, however, is primarily a 2-D design tool with some, but limited 3-D capabilities. It is very simple compared to any parametric solid modeller (although 3D is improved in AutoCAD 2007). Autodesk (the manufacturer of AutoCAD) makes a product that is nearly identical to SolidWorks, called Inventor, which is a parametric program for design of solid parts and assemblies.

SolidWorks is a 3D mechanical CAD (computer-aided design) program that runs on Microsoft Windows. SolidWorks files use the Microsoft Structured storage file format. This means that there is various files embedded within each SLDDRW (drawing files), SLDPRT (part files), SLDASM (assembly files), with preview bitmaps and metadata sub-files. Various third-party tools can be used to extract these sub-files, although the sub-files in many cases use proprietary binary file formats. SolidWorks is a parasolid-based solid modeller, and utilizes a parametric feature-based approach to create models and assemblies. Parameters refer to restrictions which values determine the shape or geometry of the model. Parameters can be either numeric, such as line lengths or circle diameters, or geometric, such as tangent, parallel, concentric, horizontal or vertical. Numeric parameters can be associated with each other through the use of relations, which allows them to capture design intent.

AutoCAD is, just like SolidWorks, a Computer Aided Design software application for 2-D and 3-D design and drafting. AutoCAD was one of the first CAD programs to run on personal or home computers, notably the IBM personal computer. At that time, most other CAD programs ran on mainframe computers or mini-computers that were connected to a graphics computer terminal for each user. Early releases of AutoCAD used basic entities such as lines, poly-lines, circles, arcs, and text to ultimately construct more complex objects. AutoCAD has since started to support custom objects through its C++ Application Programming Interface (API).

Modern AutoCAD includes a full set of basic solid modelling and 3-D tools. With the release of AutoCAD 2007 improved 3D modelling saw the light, which means better navigation when working in three dimensions. It also became easier to edit 3-D models. The mental ray engine was included in rendering and thus it was now possible to do quality renderings. AutoCAD 2010 introduced parametric functionality and network modelling. At this moment, AutoCAD only runs under Microsoft Windows operating systems. It is available in 32-bit and 64-bit versions. AutoCAD can run on an emulator or compatibility layer like VM-ware Workstation or Wine, although various performance issues can arise if you work with 3-D objects or large drawings.

Choosing a system that works for you depends solely on the type of work you want to do. Many experts say that SolidWorks is more effective when working on 3 dimensional designs and that AutoCAD is the way to go for 2 dimensional design.

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