acoustics-workshop1-kw - 副本.docVIP

Note: This workshop provides instructions in terms of the ABAQUS Keywords interface. If you wish to use the ABAQUS GUI interface instead, please see the “Interactive” version of these instructions. Please complete either the Keywords or Interactive version of this workshop. Goals When you complete this workshop, you will be able to: Determine the natural frequencies of an acoustic domain. Determine the steady-state dynamic response of an acoustic system. Define a classical acoustic plane-wave absorbing boundary. Define acoustic excitation loads. View real and imaginary components of acoustic pressure with ABAQUS/Viewer. Use ABAQUS/Viewer to create path plots of acoustic output data. Introduction A simple acoustic model of a section of air duct will be used to introduce some of the basic analysis techniques that can be applied to an acoustic mesh. In this workshop you will add important modeling details to complete the supplied analysis input file that already contains basic modeling data such as node, element, and material definitions, for the air duct section shown in Figure W1–1. The model for this workshop represents only the air inside the duct. Therefore, the acoustic natural boundary condition of infinite impedance at a mesh boundary implies rigid duct walls. You will perform natural frequency extraction analyses with different sets of acoustic boundary conditions assigned to the ends of the duct. You will then perform a series of steady-state dynamic response analyses on the model using different excitation methods. The steady-state dynamic analyses will also include the definition of acoustic plane-wave absorbing boundary impedance at one end of the duct to investigate postprocessing of traveling waves for frequency-domain solutions. The air duct section model shown in Figure W1–1 is supplied to you in terms of an input file, which uses the ABAQUS parametric input capability. The parameter values defined in the input file should not be changed for this work