What is the modular ratio?
Modular Ratio is defined as the Ratio between Modulus of Elasticity of Steel and Modulus of Elasticity of Concrete. This is because, a Reinforced Concrete is made up of Both Steel and Concrete. In this case, Steel is a Tension member and Concrete is a Compression Member.
How is modular ratio calculated?
This is done by transformation using the modular ratio m which is the ratio of modulus of elasticity of steel and concrete. Thus, m = Es/Ec. where Es is the modulus of elasticity of steel which is 200000 N/mm2. However, concrete has different moduli, as it is not a perfectly elastic material.
How do you find the section modulus of a composite section?
The elastic section modulus is defined as S = I / y, where I is the second moment of area (or moment of inertia) and y is the distance from the neutral axis to any given fiber. It is often reported using y = c, where c is the distance from the neutral axis to the most extreme fiber , as seen in the table below.
What is the significance of modular ratio in design?
Modular ratio is the ratio of Modulus of Elasticity of Steel to Modulus of Elasticity of Concrete, Modular ration significance is to finding losses in prestress. because of the influence of creep. Reinforced concrete is made up of two material,ie,concrete and steel.
Why modular ratio is not used in LSM?
The real strength of the structure is not completely utilized by the structure. This won’t give the true factor of safety of the structure when it is under failure. The modular ratio design will end up giving a structure with a large percentage of steel and uneconomical design.
What is meant by Poisson’s ratio?
Poisson’s ratio is defined as the ratio of the change in the width per unit width of a material, to the change in its length per unit length, as a result of strain.
What is the limit to Poisson’s ratio?
The Poisson’s ratio of a stable, isotropic, linear elastic material must be between −1.0 and +0.5 because of the requirement for Young’s modulus, the shear modulus and bulk modulus to have positive values. Most materials have Poisson’s ratio values ranging between 0.0 and 0.5.
What is negative Poisson’s ratio?
Auxetics are structures or materials that have a negative Poisson’s ratio. When stretched, they become thicker perpendicular to the applied force. This occurs due to their particular internal structure and the way this deforms when the sample is uniaxially loaded.
Can Poisson’s ratio be greater than 1?
Poisson’s ratios exceeding 1/2 are permissible in an- isotropic materials. Indeed, hexagonal honeycombs can exhibit Poisson’s ratio of 1, and if they have oriented hexagonal cells, greater than 1, in certain directions [2].
How do you calculate Poisson’s ratio?
Poisson Ratio Formula where μ = Poisson’s ratio, εt = transverse strain (m/m, or ft/ft) and εl = longitudinal or axial strain (again m/m or ft/ft). Young’s modulus and Poisson’s ratio are among the most important quantities in the area of stress and strain engineering.
Why is Poisson’s ratio always positive?
Since most common materials become thinner in cross section when stretched, Poisson’s ratio for them is positive. The reason is that inter-atomic bonds realign with deformation.
Is Poisson’s ratio positive or negative?
One of the important mechanical properties of materials is Poisson’s ratio, which is positive for most of the materials. However, certain materials exhibit “auxetic” properties; that is, they have a negative Poisson’s ratio. Thus auxetic and non-auxetic materials exhibit different deformation mechanisms.
What is Young’s modulus and Poisson’s ratio?
Poisson’s ratio is related to elastic moduli K (also called B), the bulk modulus; G as the shear modulus; and E, Young’s modulus, by the following (for isotropic solids, those for which properties are independent of direction). The elastic moduli are measures of stiffness. They are ratios of stress to strain.
What is the SI unit of bulk modulus?
Pascal
What is the ratio of bulk modulus?
In the English system the bulk modulus may be expressed in units of pounds per square inch (usually abbreviated to psi), and in the metric system, newtons per square metre (N/m2), or pascals. The value of the bulk modulus for steel is about 2.3 × 107 psi, or 1.6 × 1011 pascals, three times the value for glass.
How bulk modulus is equal to pressure?
Bulk Modulus is a measure of the resistance of a fluid to compression. It is defined as the ratio of pressure stress to volumetric strain. The value of bulk modulus equals the pressure change x 100 required to cause a one percent change in volume.
Why is bulk modulus negative?
The negative sign indicates that an increase in pressure is accompanied by a decrease in volume. meaning that it requires an enormous pressure to change the volume of water by a small amount. For all practical purposes water (and many other liquids as well) is treated as being incompressible.
What is the modulus of resilience?
The modulus of resilience is defined as the maximum energy that can be absorbed per unit volume without creating a permanent distortion. It can be calculated by integrating the stress–strain curve from zero to the elastic limit.
What is the ratio of bulk modulus of elasticity?
Ratio of stress to change in volume of a material subjected to axial loading. Related to Modulus of Elasticity (E) and Poisson’s Ratio (r) by the following equation: Bulk Modulus K=E/3(1-2r).