AERONAUTICAL LECTURING NOTES

Elastic Region (Point 1 –2) When we start to apply tensile pull on the specimen, the stress and strain develops,keeps on increasing in a  proportional  manner upto elastic limit. The material will return to its original shape after the material is unloaded (like a rubber band). The stress is linearly proportional to the strain in this region. Point 2: Yield Strength: A point where permanent deformation occurs.  (If it is passed, the material will no longer return to its original length.) Tensile Strength (Point 3) The largest value of stress on the diagram is called  Tensile Strength (TS) or Ultimate Tensile Strength (UTS).  It is the maximum stress which the material can support without breaking. Point 4: Strain Hardening If the material is loaded again from Point 4, the curve will follow back to Point 3 with the same Elastic Modulus (slope). The material now has higher yield strength of Point 4. Raising the yield strength by p...

Define stress. When an external force acts on a body, it undergoes deformation. At the same time the body resists deformation. The magnitude of the resisting force is numerically equal to the applied force. This internal resisting force per unit area is called stress. Stress = Force/Area     N/m 2 Define strain When a body is subjected to an external force, there is some change of dimension in the body. Numerically the strain is equal to the ratio of change in length to the original length of the body. Strain = Change in length/Original length e = δ L/L Define- elastic limit Some external force is acting on the body, the body tends to deformation. If the force is released from the body it regain to the original position. This is called elastic limit. State Hooke’s law It states that when a material is loaded, within its elastic limit, the stress is directly proportional to the strain. Stress α Strain σ α e Define – Young’s modulu...