Compressive and tensile structural elements having an enclosure with walls surrounding a cavity. A non-compressible material is disposed in the cavity. The walls are shaped such that a force tending to compress or elongate the element by a first deflection causes an amplified second deflection of the walls into the non-compressible material. The second deflection exerts a compressive force against the non-compressible material, resulting in a resistance to the first deflection and the force tending to compress or elongate the structural element. The walls of the elements are configured for optimum rigidity and/or optimum damping. Structural beams and motion impartation devices utilize the structural elements to provide lightweight rigidity and/or damping.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional application of Ser. No. 09/575,548 filed May 22, 2000, which is a divisional application of Ser. No. 09/177,137 filed Oct. 21, 1998, now U.S. Pat. No. 6,082,072, which is a divisional application of Ser. No. 08/934,402 filed Sep. 19, 1997 now U.S. Pat. No. 6,054,197.
