Abstract: A method and system for designing a door seal system is based upon a predicted contribution of the door seal system to sound pressure levels (SPLs) within a vehicle due to wind noise. A door seal system design is selected and a door seal system deformed geometry is determined. The deformed door seal system and acoustic media are combined to produce a fully coupled acoustic/structure model of the door seal system. A sound transmission loss is predicted for the door seal system design under predetermined conditions using acoustics, finite deformation rubber elasticity, and steady state harmonic viscoelasticity. The sound transmission loss and interior SPLs are then displayed, and the door seal design changed according to predefined rules to produce a seal design which provides a desired SPL in the vehicle.

Abstract: An apparatus and method for determining the dynamic response of a physical structure is disclosed. A single sheet of a piezoelectric polymer film, preferably polyvinylidene fluoride, or PVDF, is coated on one side with a thin layer of conductive material to serve as a ground electrode. The other side of the sheet is coated with a thin layer or conductive material in a non-contiguous pattern of individual electrodes defining an array of discrete piezoelectric transducers. Sensor leads are connected to each individual electrode and lead to a signal processor which includes associated software for determining from the processed electrical signals relative strain amplitudes of the surface area of a physical structure onto which the sheet is attached. The resulting output can be used to record strain time histories for later processing or, more simply, to show the time-averaged, steady state strain response of a structure.

Abstract: A digital programmable ultrasonic generator for driving an ultrasonic transducer includes a computer for receiving and storing a plurality of selectable programs. The programs are indicative of different modes of operation. A profile generator is coupled to the computer to receive programs and to produce a digital reference voltage indicative of a voltage profile to be generated for the mode selected. A digital frequency controller is coupled to a direct digital synthesizer for producing a predetermined frequency in response to a programmed frequency command from the computer. A process controller receives the output of the direct digital synthesizer as a voltage signal having the desired frequency and modifies the voltage depending on the mode of operation and voltage desired before driving a power amplifier coupled to the transducer to be driven.