Abstract: System and methods for characterizing a response of a structure-under-test to applied excitation forces using a test fixture. The fixture is selectively coupleable to the structure-under-test and is configured to hold the structure-under-test at a known position and in a known orientation relative to the fixture. A plurality of excitation devices and response sensors are coupled to the fixture. Excitation forces applied to the fixture by the excitation devices are conveyed by the fixture to the structure-under-test and each response sensor measures a dynamic response indicative of a response of the structure-under-test and the fixture to the applied excitation force. A controller receives response sensor data and applies a mathematical coordinate transformation to project the forces and moments corresponding to the applied excitation and the measured dynamic responses to a target point of the structure-under-test and to calculate a system response function based at least in part on the projection.

Abstract: Systems and methods for automated MIMO force-response characterization of a structure-under-test. The structure-under-test is coupled to a plurality of exciter devices and a plurality of response sensors. An excitation signal is automatically and iteratively applied to each exciter device while sensor data is collected from each response sensor to collect response data for a plurality of different exciter-sensor combinations (i.e., response data collected by a single response sensor while the excitation signal is applied to a single exciter device). A signal quality test is applied to the collected sensor data and, in response to determining that the collected response data for a particular exciter-sensor combination is of insufficient quality, the data collection for that exciter-sensor combination is automatically repeated. The excitation signal can be automatically adjusted before repeating the data collection to improve the quality of the collected data for the exciter-sensor combination.

Abstract: System and methods for characterizing a response of a structure-under-test to applied excitation forces using a test fixture. The fixture is selectively coupleable to the structure-under-test and is configured to hold the structure-under-test at a known position and in a known orientation relative to the fixture. A plurality of excitation devices and response sensors are coupled to the fixture. Excitation forces applied to the fixture by the excitation devices are conveyed by the fixture to the structure-under-test and each response sensor measures a dynamic response indicative of a response of the structure-under-test and the fixture to the applied excitation force. A controller receives response sensor data and applies a mathematical coordinate transformation to project the forces and moments corresponding to the applied excitation and the measured dynamic responses to a target point of the structure-under-test and to calculate a system response function based at least in part on the projection.

Abstract: An exciter device is configured to apply both a vibrational force and an impact force to a device-under-test. A first end of a piston is couplable to the device-under-test and a second end of the piston is aligned with a position of an impact hammer tip. The impact hammer tip and an electromagnet are both coupled to a moveable housing that is positioned around the piston. The exciter device applies a vibrational force to the device-under-test when an alternating magnetic field is applied by the electromagnet to the permanent magnet causing a linear reciprocating movement of the moveable housing relative to the piston. The exciter device applies an impact force to the device-under-test when a magnet field is applied by the electromagnet to the permanent magnet causing a linear movement of the moveable housing that is sufficient to cause the impact hammer to contact the second end of the piston.

Abstract: A suspension system for an exciter device. The exciter device includes a piston extending through an opening of a moveable housing and generates a vibrational force by causing a linear reciprocating movement of the housing relative to the piston. The suspension system includes an axial suspension magnet fixedly coupled to the housing and positioned proximate the opening. The axial suspension magnet is configured to oppose a magnetic field of a permanent magnet that is fixedly coupled to the piston and the opposing magnetic fields dampen movement of the housing relative to the piston as the first axial suspension magnet approaches the permanent magnet. A radial guide bushing is positioned within the opening surrounding a circumference of the piston. The radial guide bushing is formed of a compressible and flexible material and is configured to restrict radial movement of the housing relative to the piston.

Abstract: A method for manufacturing a shaker device using 3D-printing (i.e., additive manufacturing). An electromagnet is formed by producing a bobbin body and winding an electrical conductor on the bobbin body to form an electromagnet coil. A cylindrical body is 3D-printed and the bobbin body with the electromagnet coil is coupled within an interior of the cylindrical body. A piston assembly is then positioned within the bobbin assembly. The shaker device is operated by controllably applying a magnetic field through the electromagnet coil that impinges a permanent magnet of the piston assembly to cause movement of the cylindrical body relative to the piston. By using these 3D printing techniques, the composition of materials can be varied within a single component part, fine structural details can be included in the components, and components can be 3D printed directly on each other to eliminate tolerance issues relating to small variations in component size.

Abstract: Systems and methods for automated MIMO force-response characterization of a device/structure-under-test. A SIMO exciter router is operated to selectively couple an excitation signal input to an exciter device while the sensor data indicative of a sensed response to the imparted excitation force is collected from a plurality of response sensors. The SIMO exciter router operates to collect sensor data for each of a plurality of different exciter-sensor combinations (i.e., sensor data is collected from each individual response sensor while the excitation force is applied by each individual exciter device). The sensor data is collected by a data acquisition system with a plurality of signal input channels each coupled to a different response sensor or a sensor router is used to selectively couple each individual sensor output to a shared signal input channel of the data acquisition system.

Abstract: Methods and systems for in-situ determination of system response functions. One example method includes coupling a controlled blocked force exciter to a calibration receiver structure. The method also includes operating the controlled blocked force exciter under controlled operation conditions to induce vibration in the calibration receiver structure and measuring response data for the calibration receiver structure. The method further includes determining blocked forces based on the response data for the calibration receiver structure. The method also includes coupling the controlled blocked force exciter to a target receiver structure. The method further includes operating the controlled blocked force exciter under the controlled operation conditions to induce vibration in the target receiver structure and measuring response data for the target receiver structure.