Adjustable stiffness assembly

An adjustable stiffness assembly for elastically connecting a structure to a mass comprising at least one mass block, the adjustable stiffness assembly having a structural stiffness value with respect to force in a direction relative to the structure, referred to as the structure direction, the adjustable stiffness assembly comprising:

• a structure mount attachable to the structure;
• a mass mount attachable to the mass, the structure mount being spaced apart from the mass mount;
• and
• a beam having a thickness, a width, and a length that is greater than the thickness and the width, extending lengthwise between the structure mount and the mass mount and being rotatably engaged with the structure mount and the mass mount, the beam having a longitudinal axis extending along the length of the beam, the beam being shaped so that a second moment of area (Ixx) of the beam around a first direction, referred to as X, orthogonal to the longitudinal axis is greater than a second moment of area (Iyy) of the beam around a second direction, referred to as Y, orthogonal to the longitudinal axis and orthogonal to the first direction,
• so that the beam has a minimum stiffness value with respect to moments about the second direction, which is less than a maximum stiffness value with respect to moments about the first direction;
• wherein the beam is securable in a fixed rotational position relative to the structure mount and the first mass mount to provide a fixed stiffness value with respect to force in the structure direction,
• and wherein the beam is rotatable relative to the structure mount and the mass mount about the longitudinal axis to vary the structural stiffness value of the adjustable stiffness assembly.

An adjustable stiffness assembly for elastically connecting a structure to a mass comprising at least one mass block, the adjustable stiffness assembly having a structural stiffness value with respect to force in a first direction relative to the structure, the adjustable stiffness assembly comprising:

• a structure mount attachable to the structure;
• a mass mount attachable to the mass, the structure mount being spaced apart from the mass mount;
• and
• a rotatable stiffness element having a thickness, a width, and a length that is greater than the thickness and the width, extending lengthwise between the structure mount and the mass mount and being rotatably engaged with the structure mount and the mass mount, the rotatable stiffness clement element having a minimum stiffness value with respect to forces in a first direction relative to the rotatable stiffness element, the first direction referred to as X, and a maximum stiffness value with respect to forces in a second direction relative to the rotatable stiffness element, the second direction referred to as Y, wherein the maximum stiffness value is greater than the minimum stiffness value;
• wherein the rotatable stiffness element is securable in a fixed rotational position relative to the structure mount and the first mass mount to provide a fixed stiffness value with respect to force in the first direction,
• and wherein the rotatable stiffness element is rotatable relative to the structure mount and the mass mount about a longitudinal axis extending in a direction orthogonal to the X and Y directions between the structure mount and the first mass block assembly mount to vary the structural stiffness value of the adjustable stiffness assembly,
• and wherein the rotatable stiffness element is a beam having a non-circular cross-section orthogonal to the longitudinal axis.