Viscoelastic damping structures and related manufacturing method

• US 5,342,465 A
• Filed: 09/28/1992
• Issued: 08/30/1994
• Est. Priority Date: 12/09/1988
• Status: Expired due to Fees

• Current Assignee: TRW Inc. (Northrop Grumman Corporation)
• Original Assignee: TRW Inc. (Northrop Grumman Corporation)
• Inventors: Kaplan, Abner, Bronowicki, Allen J.
• Primary Examiner(s): Simmons, David A.
• Assistant Examiner(s): Rainwater, Charles
• Application Number:
  US07/952,012
• Time in Patent Office: 701 Days
• Field of Search: 156/190, 156/191, 156/192, 156/173, 156/175, 156/290, 156/291, 156/193, 428/113, 428/107, 428/229, 428/36.4, 428/36.8
• US Class Current: 156/175
• CPC Class Codes: B32B 3/14 characterised by a face layer formed of separate pieces of material which are juxtaposed side-by-side B32B5/02 takes precedence
• CPC Class Codes: B64G 1/22 Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
• CPC Class Codes: F16F 9/30 with solid or semi-solid material, e.g. pasty masses, as damping medium in devices where rotary elements are damped by viscous shear effect only, any throttling effect being immaterial F16F9/12; where members moving with a rotating system are being damped F16F15/16

Abstract

A composite structure of elastic and viscoelastic components in which dynamic loads are effectively damped by transmission through the viscoelastic components. The structure includes a continuous sandwich comprised either of a single elastic layer enclosed by two viscoelastic layers or of a single viscoelastic layer enclosed by two elastic layers such that the sandwich has little stiffness in any intended direction of loading, and two segmented elastic layers having stiffness in a desired loading direction. The segmented layers have alternating segments and gaps and are disposed one on each side of the viscoelastic layer in such a manner that the gaps of one segmented layer overlap the segments of the other segmented layer. Dynamic loads in the loading direction are transmitted back and forth from one segmented layer to the other, through the continuous sandwich layer containing the viscoelastic material, which thereby provides a high degree of damping. Static loads in the loading direction are transmitted through the elastic material in the continuous sandwich layer. By appropriate selection of elastic materials, the structure can be made suitable for the damping of loads in all directions while maintaining considerable strength and static stiffness. Appropriate selection of fiber orientations can increase the damping effect on either axial and bending loads, or on torsional loads.

Claims

1. A method for fabricating a tubular viscoelastic damping structure, comprising the steps of:

placing annular spacers on a cylindrical mandrel;

forming an inner segmented layer on the mandrel in segment regions between the spacers;

forming an inner sandwich portion comprising multiple continuous layers including viscoelastic material and elastic material over the inner segmented layer;

curing the resulting structure of inner segmented layer and inner sandwich portion;

forming an outer segmented layer over the sandwich portion, wherein the outer segmented layer has segments that partially overlap the segment regions of the inner segmented layer;

curing the entire structure; and

removing the mandrel and the annular spacers.

2. A method as defined in claim 1, wherein the step of forming the sandwich portion includes forming a core layer of elastic material, forming two layers of viscoelastic material, one on each side of the core layer, and forming a thin sealing layer over the viscoelastic layer.

3. A method as defined in claim 1, wherein:

the sealing layer is of Kapton.

4. A method as defined in claim 1, and further comprising:

placing additional annular spacers over the structure prior to the step of forming an outer segmented layer.