<b>Crack problems concerning boundaries of convex lens like forms</b> The singular stress problem of aperipheral edge crack around a cavity of spherical portion in an infinite elastic medium whenthe crack is subjected to a known pressure is investigated. The problem is solved byusing integral transforms and is reduced to the solution of a singularintegral equation of the first kind. The solution of this equation is obtainednumerically by the method due to Erdogan, Gupta , and Cook, and thestress intensity factors are displayed graphically.Also investigated in this paper is the penny shaped crack situated symmetrically on the central plane of a convex lens shaped elastic material. cavity of spherical portion peripheral edge crack penny shaped crack SIF. 982-997 Issue-3 Volume-2 Doo-Sung Lee