principle of virtual work structural analysis examples

A steel member is capable of absorbing considerable deformation, beyond the limit of elasticity without fracture or collapse. This has been possible due to the unique property of ductility possessed by steel. Plastic designs consider the capacity of members to continue offering resistance even after reaching the yield stress. In plastic designs importance is given to resistances to bending caused by loads when the members are in the plastic range. Ultimate loads which cause the collapse are determined by multiplying the working loads by a load factor. The method therefore takes into account the behaviour of a member as it is stressed beyond the yield stress, in the inelastic or plastic range. Plastic method adopts the ultimate strength as the criterion for design.

A relatively large part of deformation occurs during the strain hardening process. A large part of this deformation occurs during yielding. its ability to resist large deformation without fracture. Structural steel has an important property viz.

In modern designs the above principle is followed and the method of design on this principle is called collapse method of design or plastic design. Due to plastic deformations and strain hardening of the material particles which were less stressed will be brought into action, so that the structure actually is able to resist greater loads.

In other words, if yield point is attained at a single point, it does not mean a state of collapse of the member. But strictly providing a factor of safety on the basis of yield stress is not a consistent indication of the factor of safety with respect to the ultimate capacity of a member. We have been providing a factor of safety based on yield stress. Designs are also made assuming that the structural members behave elastically. Introduction to Plastic Analysis:Īnalysis of stress, deflection and distortion determinations within the limit of proportionality of the material of a structure have been satisfactorily made. Relation between Load Factor and Factor of Safety. Plastic Moment of Resistance of a Symmetrical I-Section 5. Moment of Resistance of a Rectangular Beam Section for a Given Depth of Penetration 4. Plastic Moment of Resistance of a Rectangular Section 3. In this article we will discuss about:- 1.

Principle of virtual work structural analysis examples