Author

Abstract

Finding the amount of plastic deformation into metallic plates,metallicstructures,
ships frame, bodies of different types of cylinders and reservoirsbodies as a result of
exposure tostaticor dynamic forceis so necessary todetermine the extent
ofdistortionand destructionhappening intheseobjects and this is one of the main
factors in design calculations to determine the dimensions and thicknesses of these
bodies. Derivation anew theoreticalmodelto calculate theamount of work and
forcerequired to bulge the sheet metalisa very important targetbecause of the lack of a
theoretical relations to calculate the work of plastic deformation with good
approximationoridenticalto exact required work and force; or vice-versa to find the
amount of plastic deformation as a result of a specific work or specific force.This was
donein this research where a theoretical model has been derivedthrough the expense
of work and force necessary to generatebulging in sheet metal. This theoretical model
has been adopted on the mildsteel plates which are of wide application in practical
life. Results obtained from the theoretical model were compared with those obtained
from tests conducted onsimply supported circular steel plates made from low carbon
steel ,milled steel , of a (280) mm diameter and (1,2, 3, 4,5, 6, 8,10) mm thickness
andexposed to central force applied by a flat ended punch of 10 mm diameter. The
applying 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 practical
resultsand those obtained from the theoretical model to find the work and for ceit
takes to plastic deformation in the tested plates.