| 摘要 |
PROBLEM TO BE SOLVED: To achieve the optimal design of a silencer so as to practically evaluate silencing performance with sufficient precision even for the punching metal or distributed holes of a silencer. SOLUTION: The structure of a silencer is fetched as CAD data, and an analytic model is created with a mesh by a finite element method. In this case, mass averaged based on plate thickness and medium density and hole diameter and the number of holes is arranged as acoustic mass at the node of each mesh configuring a section where the punching metal can be arranged. Then, the insertion loss of a closed edge side and an open edge side is calculated as silencing performance by frequency response analysis, and target performance to initial performance is set, and silencing performance for individually changing the acoustic mass is analyzed, and sensitivity due to the change of each acoustic mass is calculated. The acoustic mass which can be better when it is made large and the acoustic mass which can be better when it is made small are extracted from the sensitivity due to the change of each acoustic mass, and silencing performance when the acoustic mass is changed in a prescribed way is analyzed, and a target achievement rate is calculated, and they are visually displayed on a monitor. COPYRIGHT: (C)2009,JPO&INPIT
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