Ronald K. Shelp, an international business economist who recently was vice president for a major worldwide insurance conglomerate, American International Group, has been named vice president and head of government relations for Celanese Corp., a Fortune 100 producer of chemicals, fibers and specialty products. He replaces Donald G. Ogilvie, who resigned in April to become executive vice president of the American Bankers Association.

Chesapeake Corp., the West Point, Va.-based producer of wood pulp and paper products, has named J. P. Harper group vice president in charge of woodlands and wood products. Harper, a 17-year veteran of the firm, replaces Thomas G. Harris, who retired Aug. 1. Under Harper's direction of the wood products division, William J. Phipps has been shifted to manager of pine lumber operations at its Elizabeth City, N.C., facility. Thomas E. Stanley has been named hardwood-lumber operations manager at West Point, replacing Phipps. And Edward M. Carter, formerly with Georgia Pacific, has joined the company as general manager of Chesapeake Plywood Inc. in Pocomoke City, Md. Separately, Chesapeake has named a Wisconsin man, Thomas J. Contrucci, to serve as a liaison between the company's corporate headquarters and its newest subsidiaries, Wisconsin Tissue Mills Inc., in Menasha, Wis., and Plainwell Paper Co. Inc., in Plainwell, Mich.

John J. Dillon, a 21-year veteran of International Business Machine Corp.'s federal systems division, has been appointed aerospace marketing manager for General Electric Corp.'s aerospace business group. Dillon, who will remain in Washington, succeeds Jack W. Hugus, now a general manager for GE's Binghamton, N.Y., aerospace operation.