Methods and systems of determining the static stiffness of a body structure

A method of assessment of sufficiency of static stiffness of a body structure, the method comprising:

• defining a static stiffness requirement;
• determining the static stiffness via a computer-implemented process;
• comparing the static stiffness requirement with the determined static stiffness;
• and,
• outputting a result of the comparison via an interface to a design process and/or a human machine interface,
• wherein the determining of the static stiffness via the computer-implemented process comprises:
• providing dynamic data;
• defining flexible-body modes of the dynamic data of the body structure;
• performing a modal decomposition of all defined flexible-body modes into contributions of rigid-body modes and a residual term, wherein the modal decomposition of the body structure is defined as:
• Ψ
• Flex
• ,
• j
• =
• ∑
• i
• =
• 1
• 6
• α
• ij
• ⁢
• Ψ
• RB
• ,
• i
• +
• R
• j
• wherein:
• ΨFlex, j is a jth flexible-body mode;
• ΨRB, i is an ith rigid-body mode;
• αij are decomposition factors of jth flexible-body mode into rigid-body mode i;
• and
• Rj is a residual term for the jth flexible mode,
• such that the residual term results as free of inertial effects;
• determining residual terms from the modal decomposition;
• and determining the static stiffness from the residual terms.

A system configured to determine a static stiffness of a body structure, the system comprising:

• at least one processor configured to:
• receive dynamic data;
• define flexible-body modes of the dynamic data of the body structure;
• perform a modal decomposition of all defined flexible-body modes into contributions of rigid-body modes and a residual term, wherein the modal decomposition of the body structure is defined as:
• Ψ
• Flex
• ,
• j
• =
• ∑
• i
• =
• 1
• 6
• α
• ij
• ⁢
• Ψ
• RB
• ,
• i
• +
• R
• j
• wherein:
• ΨFlex, j is a jth flexible-body mode;
• ΨRB, i is an ith rigid-body mode;
• αij are decomposition factors of jth flexible-body mode into rigid-body mode i;
• and
• Rj is a residual term for the jth flexible mode,
• such that the residual term results as free of inertial effects;
• determine residual terms from the modal decomposition;
• and determine the static stiffness from the residual terms.