Theoretical Evaluation of Required PlasticWork in Bulging of Statically loaded Plate


Finding the amount of plastic deformation into metallic plates,metallicstructures,ships frame, bodies of different types of cylinders and reservoirsbodies as a result ofexposure tostaticor dynamic forceis so necessary todetermine the extentofdistortionand destructionhappening intheseobjects and this is one of the mainfactors in design calculations to determine the dimensions and thicknesses of thesebodies. Derivation anew theoreticalmodelto calculate theamount of work andforcerequired to bulge the sheet metalisa very important targetbecause of the lack of atheoretical relations to calculate the work of plastic deformation with goodapproximationoridenticalto exact required work and force; or vice-versa to find theamount of plastic deformation as a result of a specific work or specific force.This wasdonein this research where a theoretical model has been derivedthrough the expenseof work and force necessary to generatebulging in sheet metal. This theoretical modelhas been adopted on the mildsteel plates which are of wide application in practicallife. Results obtained from the theoretical model were compared with those obtainedfrom tests conducted onsimply supported circular steel plates made from low carbonsteel ,milled steel , of a (280) mm diameter and (1,2, 3, 4,5, 6, 8,10) mm thicknessandexposed to central force applied by a flat ended punch of 10 mm diameter. Theapplying force was increased gradually till it caused plastic deformation in the sheet,and then reached the state of shear of the disk, which is locatedunder the punch.Results comparison appear matchorsubstantial convergence between the practicalresultsand those obtained from the theoretical model to find the work and for ceittakes to plastic deformation in the tested plates.