Abstract: The process for forming a metallic sandwich structure having a curved surface, particularly a surface curving about more than one axis, such as a quadric surface partially by direct displacement and partially by a fluid interface. Additionally, means to restrain the work sheets being formed with respect to the shaping fixture which allow a portion of the work sheets to flow into the forming cavity before absolute restraint is applied and the restraining means function independently of the clamping force of the press.

Abstract: The process for forming a metallic sandwich structure having a curved surface, particularly a surface curving about more than one axis, such as a quadric surface partially by direct displacement and partially by a fluid interface. Additionally, means to restrain the work sheets being formed with respect to the shaping fixture which allow a portion of the work sheets to flow into the forming cavity before absolute restraint is applied and the restraining means function independently of the clamping force of the press.

Abstract: An apparatus and method for controlling the superplastic forming process by measuring and controlling the volume displaced by the blank being formed so as to measure total strain or surface area increase of the blank.

Abstract: The structure and the process for making a metallic sandwich structure in which metal worksheets, preferably made from titanium alloy, are joined in a preselected pattern by an intermittent or discontinuous weld. The joined sheets are sealed by a continuous weld to form an expandable envelope. Application of inert gas pressure to the envelope in a limiting fixture superplastically produces the sandwich structure as the expanded structure diffusion bonds to itself or other worksheets. Core configuration of the structure is determined by the intermittent weld pattern. Face sheets of the sandwich structure may be formed from one sheet of the envelope or may be inserted in the limiting fixture and the envelope expanded against the face sheets. Additionally, the face sheets may be preformed or formed concurrently with the core to produce the desired core and sandwich shape in a single operation.

Abstract: The structure and the process for making a metallic sandwich structure in which metal worksheets, preferably made from titanium alloy, are joined in a preselected pattern by an intermittent or discontinuous weld. The joined sheets are sealed by a continuous weld to form an expandable envelope. Application of inert gas pressure to the envelope in a limiting fixture superplastically produces the sandwich structure as the expanded structure diffusion bonds to itself or other worksheets. Core configuration of the structure is determined by the intermittent weld pattern. Face sheets of the sandwich structure may be formed from one sheet of the envelope or may be inserted in the limiting fixture and the envelope expanded against the face sheets. Additionally, the face sheets may be preformed or formed concurrently with the core to produce the desired core and sandwich shape in a single operation.