yes

Rohit Ralli , Yes, its the inverse of Stiffness matrix. Hooke's law can be written in either way i.e., stiffness or compliance form. Be it static or dynamic problem, you can directly invert the compliance matrix (for displacement proportional term) and use it in the EOM. Same applies to classical damping assumption like Rayleigh for estimating the damping coefficients.

Thanks pranoy.

so when we talk about the axial pile compliance, what does it mean?

Rohit Ralli , I would say compliance (flexibility) of the pile along its length. As I am coming from N&V background, I would like to throw some insights on the processing of dynamic responses. When looking at dynamic responses, quite often we look at the response of the structure for an unit loading to understand the system's behavior. So, if we go with the simple uni-axial equation, compliance can be defined as displacement per unit load acting in the principal direction. If the structure that you are analyzing has any modal content corresponding to external excitation, the response(compliance) plot will show that how easily your structure can deviate *in that principal direction* from the ideal *rigid body* (ideal for N&V) compliance curve at resonance conditions which can be very well controlled with damping in the system. Same holds good for the inverse of velocity and acceleration responses.

Sorry for throwing supplementary information.

Pranoy Nair thanks, that what I was looking for.

so that means if for a particular load it’s compliance is more that means it will displace more and it’s stiffness will be less for that pile system ?

Rohit Ralli Yes, that can be inferred.