tubular area 58 is substantially filled with at least one shear thickening material 70 see fig5 chosen to achieve at least a second predetermined assembly resonant frequency similar to the first predetermined assembly resonant frequency note that fig5 schematically represents a partially sectioned view of an instantaneous configuration of the shear thickening material 70 within circumferential tubular area 58 in an alternate invention embodiment a tunable valve assembly 99 comprises a valve body 10 substantially symmetrical about a longitudinal axis valve body 10 having a peripheral groove 12 spaced apart from a central longitudinal guide stem 14 by an annular reservoir 16 groove 12 is responsive to longitudinal compressive force on tunable valve assembly 99 see discussion above viscoelastic elements 50 comprising reservoir element 52 and groove element 54 are integrated with i e lie substantially in reservoir 16 and groove 12 respectively an adjustable preload flange 30 is coupled to guide stem 14 and contacts viscoelastic reservoir element 52 in reservoir 16 to impose an adjustable annular constraint on viscoelastic reservoir element 52 for achieving at least a first predetermined assembly resonant frequency substantially replicating a measured resonant frequency e g a pump housing resonant frequency such adjustable annular constraint imposes an adjustable shear preload between constrained annular area 62 and unconstrained annular area 60 tunable valve assembly 99 may additionally comprise at least one circumferential tubular area 58 in groove element 54 residing in groove 12 each tubular area 58 being substantially filled with at least one shear thickening material 70 chosen to achieve at least a second predetermined assembly resonant frequency similar to the first predetermined assembly resonant frequency.