On the Nonlinear Dynamics and Quasi-Statics of Tape Joined Structures

Technical Report · Wed Aug 01 00:00:00 EDT 2012

DOI:https://doi.org/10.2172/1051728· OSTI ID:1051728

Segalman, Daniel Joseph ^[1]; Starr, Michael James ^[1]

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1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Tape joints have been a key tool in assembly of nuclear weapons for almost 40 years. In that time sufficient experience has been gained to have confidence on the robustness of this technology within established design constraints; the structural dynamics of systems assembled by tape joints are much less well understood. Though there is lore that tape joined structures behave linearly in the axial direction, even that is contradicted by the literature, where such structures are found to be bi-linear (nonlinear) in axial modes. Experimental results presented here show much more significant nonlinearity when such systems vibrate in such a way that there is bending across the joint cross-section. In addition, it will be difficult to understand the nonlinear structural dynamics before the pre-loads on the tape joints is known. Therefore, a strategy to deduce the joint pre-loads from surface strain measurements has been developed. This technique exploits finite element analysis to generate an approximate Green’s function to map tape loads to surface strain and employs numerical optimization to solve an inverse problem. This technique is demonstrated on the same test specimen employed in the dynamics experiments.

• Research Organization: Sandia National Lab. (SNL-CA), Livermore, CA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1051728
• Report Number(s): SAND--2012-6527
• Country of Publication: United States
• Language: English