Adjustable stiffness assembly

A tuned mass damper comprising:

• a mass block assembly;
• and
• a damper stiffness assembly comprising:
• a fixed stiffness element attached to the mass block assembly, the fixed stiffness element providing stiffness with respect to force in a global direction;
• and
• an adjustable stiffness assembly having a stiffness value with respect to force in the global direction, the adjustable stiffness assembly comprising:
• a structure mount attachable to a structure;
• a first mass block assembly mount attached to the mass block assembly, the structure mount being spaced apart from the first mass block assembly mount;
• and
• a first rotatable stiffness element extending between the structure mount and the first mass block assembly mount and being rotatably engaged with the structure mount and the mass block assembly mount, the first rotatable stiffness element having a minimum stiffness value with respect to forces in a local direction referred to as X, and a maximum stiffness value with respect to forces in another local direction referred to as Y, wherein the maximum stiffness value is greater than minimum stiffness value,
• wherein the damper stiffness assembly elastically connects the mass block assembly and the structure;
• and wherein the first rotatable stiffness element is rotatable relative to the structure mount and the first mass block assembly mount to vary the total stiffness value of the damper stiffness assembly with respect to force in the global direction.

An adjustable stiffness assembly for elastically connecting a structure to a mass, the adjustable stiffness assembly having a global stiffness value with respect to force in a global 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 first rotatable stiffness element extending between the structure mount and the mass mount and being rotatably engaged with the structure mount and the mass mount, the first rotatable stiffness element having a minimum stiffness value with respect to forces in a local direction referred to as X, and a maximum stiffness value with respect to forces in another local direction referred to as Y, wherein the maximum stiffness value is greater than minimum stiffness value;
• wherein the first rotatable stiffness element is rotatable relative to the structure mount and the mass mount to vary the global stiffness value of the adjustable stiffness assembly.