What is Elastic Modulus?

An elastic modulus, also popular as the modulus of elasticity, can be described as the quantification of the force’s ratio applied to an object or substance to the ultimate deformation. In the simplest form, you can understand that it is a measurement of how conveniently any object can be stretched or bent.

What are the Major Types of Elastic Modulus?

Elastic Modulus can be of three major kinds including Bulk Modulus, Young’s Modulus, and Shear Modulus. This article will help you understand the elastic moduli in detail.

1. Bulk Modulus: Bulk modulus is the amount of volumetric stress correlated to the strain of specified pieces of material while you can observe that the material deformation is under the elastic limit. In simple words, it is a numerical constant that is adapted to determine and explain the elastic properties of fluid and solid when pressure is exerted upon all the surfaces. Bulk modulus is a property that suggests the fluid’s compressibility. If you ignore it despite a large number of hydraulic systems today functioning at pressures 5000 psi and higher, you may find a compromised response time of a system.

2. Young’s Modulus: Young’s modulus is a count of the capability of a material to resist changes in length when you see it under lengthwise compression and tension. It quantifies the material’s resistance to recoverable (elastic) deformation under load. This would be interesting for you to know that a stiff material possesses a high Young modulus and makes changes slightly in its shape under elastic loads (e.g. diamond). Contrary to it, you will find a low Young’s modulus in a flexible material that changes shape considerably (e.g. rubbers). This property allows forces can be withstood by materials without excessive deformation.

3. Shear Modulus: The Modulus of rigidity, commonly known as Shear modulus, quantifies the body’s rigidity, provided by the proportion of shear stress to strain. This resourceful property will inform you in advance of the relationship between shearing deformation and resistance of a material. A higher value of shear modulus suggests the high rigidity of the solid while the lower value indicates a flexible or soft solid. In other words, if you observe the higher shear modulus, it means you require a large force to create deformation while little force is required to deform in the case of lower shear modulus.

Factors Affecting Elastic Modulus in Materials

Here, you’ll find the key factors that affect elastic modulus in materials.

• Structure of Material: Elastic modulus is significantly impacted by the material structure because of the properties of the material such as bonding and atomic structure. The elastic modulus’s value will be greater in case of variations in the internal structure (e.g. treatment of heat) of a material that enhances the stiffness. If you face this situation, increase the material’s porosity which would decrease the structural stiffness and lead to a lower elastic modulus. Polymerization and degree of cross-linking increase the rigidity thus enhancing Young’s Modulus as greater degrees of cross-linking lead towards higher values of modulus.
• Material Composition: The composition of the material is also one of the important factors that can pose an impact on the value of elastic modulus. This is because you can identify different materials that possess different elasticity and stiffness. For instance, a higher modulus is observed in metals like steel because of their powerful metallic bonds while the lower modulus in rubbers as they have weak intermolecular forces. You can also engineer the composite materials in order to get particular moduli, ensuring their diverse applications.
• Elongation: There is a significant relationship between elastic modulus and elongation such as the formula shows that: MOE = EI. I indicate the change in elongation while E is the Young modulus of Elasticity. Resultantly, if you observe the decrease in elongation, it means that the elasticity of modulus is increasing.
• Impacts of impurities: You can see the impacts of elasticity on an object while adding impurities. If you find that mixed impurity possesses more elasticity than an object, then the object’s elasticity gets increased. Young’s modulus reduces with impurities of material because of the reduced strength of bonding and dislocations.
• Temperature: With the increase in temperature, the modulus of elasticity expectedly decreases and the decrease rate remains almost 5GPa/100°C. If the temperature increases in the metal material, it enhances the atoms’ vibration, which will ultimately reduce the atomic forces and increase the atomic distance. You may also alter the materials’ rigidity via processes of heat treatment, impacting their elastic behaviour.
• Change of Length: This is one of the important factors affecting elastic modulus. The change in length usually affects the units that are cancelled out in the measurement and does not have any impact on the values of elastic material. The elastic modulus cannot be changed by altering specimen dimensions as it is a material property depending upon the weight, size, smell, taste, dimension, etc.

How to Select Materials Based on Elastic Modulus?

You might find it difficult to choose materials on the basis of elastic modulus but it is essential in order to achieve optimal performance and ensure cost-efficiency. Here, you find the way to make the appropriate selection of the materials.

1. Data Collection: To obtain elastic modulus data is crucial to make fine decisions for the selection of materials. You may be required to conduct compressive or tensile tests on a material sample. A compressive or tensile test is a kind of mechanical testing that exerts a force upon the sample and determines the ultimate variation in length, or strain. You can also utilise a universal testing machine for obtaining initial data or to conduct compressive or tensile tests.

2. Compare Materials: Once you have collected elastic modulus data using different testing methodologies, make a comparison of different materials and select the suitable one for the application. You may choose low or high elastic modulus, or a blend of both, depending on your design needs. It is essential to be aware of the type of modulus calculation chosen when comparing the results of modulus for a given material between multiple laboratories.

3. Examine the Stiffness: When selecting materials based on the elastic modulus, you need to choose the materials that are stiffer and show much resistance to being deformed. Commonly, if the elastic modulus is greater, it means that the material is more resistant and stiffer. On the other hand, if the elastic modulus is lower, it shows that the material is more ductile and flexible. You may also use Young’s modulus when choosing engineering material for a particular purpose it will help you know the stiffness.

4. Application: It would be appropriate for you to choose the material as per the requirements of the design of your application. For instance, rubbers can be used if you require to make dampers and joints while steel for the development of the main structure. You may also use the materials selection charts that are adopted to quantitative portrayal of the materials option present to meet the application needs. One of the most valuable means to decide on materials that are according to your design needs is by evaluating the maintenance, stability, aesthetics, and cost of each material.

5. Calculate the Deflections: Elastic modulus data that you have earlier collected will support you to measure the displacements, or deflections under multiple loads found in your design. You are required to apply formulas that relate to the loading situation of your design, the elastic modulus, and the geometry to calculate the deflections. Deflections are significant to acknowledge as they impact the aesthetics, functionality, and design’s stability.

6. Performing Cost-benefit Analysis: It would be valuable to conduct cost-benefit analysis when choosing the right materials on the basis of elastic modulus. A cost-benefit analysis will help you to determine the benefits of an action or decision minus its connected costs to examine whether it is worthwhile.

Conclusion

The knowledge of Elastic Modulus is significant as it results in making the right design on the selection of material, and ultimately leads towards optimal performance, cost efficiency, and safety. Having the understanding of modulus types, factoring affecting, and the best way to select the material, can help you and the concerned businesses to ensure efficacy and resilience across various industrial applications.