We present the СATEС software, which implements the solution to the problems of computational acoustics. The software is based on the use of the superelement method and finite element modeling algorithms, in-cluding...We present the СATEС software, which implements the solution to the problems of computational acoustics. The software is based on the use of the superelement method and finite element modeling algorithms, in-cluding hydrodynamic noise. The paper presents the main possibilities of software for solving acoustic design problems. .展开更多
传统的暖通空调(heating, ventilation and air conditioning, HVAC)系统声学设计多依赖于设计人员的经验,重复性工作多,自动化水平低。为实现智能化设计,应用有向无环图、带权有向邻接矩阵、科学计算可视化等方法将通风管道消声系统的...传统的暖通空调(heating, ventilation and air conditioning, HVAC)系统声学设计多依赖于设计人员的经验,重复性工作多,自动化水平低。为实现智能化设计,应用有向无环图、带权有向邻接矩阵、科学计算可视化等方法将通风管道消声系统的声学设计过程系统化。提出一种能够自动计算管道内任意处噪音及特定的房间内噪声值的算法,包括三维模型构建,噪声衰减图生成,声学路径确定,声学单元解算,声学结果可视化等关键环节。实验结果表明:该系统鲁棒性强,计算结果准确,响应快速。所提算法结果与设计人员利用传统方法计算出的结果误差不超过±2%,计算时长均小于0.2 s,常见的中小规模的通风系统计算时间则在0.1 s以内。基于此算法计算得出的噪声值结果能够与三维模型结合,直观展示噪声分布情况,在通风空调系统设计过程中提供参考依据。展开更多
In order to solve the severe vibration problems of an ocean engineering ship with a full-revolving propulsion system, the navigation tests, including forced vibration response test and modal test, are carded out in it...In order to solve the severe vibration problems of an ocean engineering ship with a full-revolving propulsion system, the navigation tests, including forced vibration response test and modal test, are carded out in its stem. It is concluded from the comparison of the time-domain waveform and spectrum from different measurement points that three main factors lead to a high-level stern vibration. Firstly, the specific dynamic stiffness of a water tank is relatively small compared with its neighbor hold, which makes it act like a vibration isolator preventing vibrational energy transmitting to the main hold. Secondly, there exists high-density local modes in the working frequency range of the main engine and thus the local resonance occurs. Thirdly, the abnormal engagement of gears caused by the large deflection of the shaft bearing due to its low mounting rigidity leads to violent extra impulse excitations at high speeds. Then the modification against the dynamic defects is given by simply improving the specific stiffness of the water tanks. And the effect is validated by the FEM calculation. Some important experience is obtained with the problems being solved, which is useful in the design of ships with the same propulsion system. It is also believed that the dynamic consideration is as important as the static analysis for the ships, and that most of the vibration problems may be avoided with a proper acoustic design.展开更多
文摘We present the СATEС software, which implements the solution to the problems of computational acoustics. The software is based on the use of the superelement method and finite element modeling algorithms, in-cluding hydrodynamic noise. The paper presents the main possibilities of software for solving acoustic design problems. .
文摘传统的暖通空调(heating, ventilation and air conditioning, HVAC)系统声学设计多依赖于设计人员的经验,重复性工作多,自动化水平低。为实现智能化设计,应用有向无环图、带权有向邻接矩阵、科学计算可视化等方法将通风管道消声系统的声学设计过程系统化。提出一种能够自动计算管道内任意处噪音及特定的房间内噪声值的算法,包括三维模型构建,噪声衰减图生成,声学路径确定,声学单元解算,声学结果可视化等关键环节。实验结果表明:该系统鲁棒性强,计算结果准确,响应快速。所提算法结果与设计人员利用传统方法计算出的结果误差不超过±2%,计算时长均小于0.2 s,常见的中小规模的通风系统计算时间则在0.1 s以内。基于此算法计算得出的噪声值结果能够与三维模型结合,直观展示噪声分布情况,在通风空调系统设计过程中提供参考依据。
基金financially supported by the National Natural Science Foundation of China(Grant No.51109131)
文摘In order to solve the severe vibration problems of an ocean engineering ship with a full-revolving propulsion system, the navigation tests, including forced vibration response test and modal test, are carded out in its stem. It is concluded from the comparison of the time-domain waveform and spectrum from different measurement points that three main factors lead to a high-level stern vibration. Firstly, the specific dynamic stiffness of a water tank is relatively small compared with its neighbor hold, which makes it act like a vibration isolator preventing vibrational energy transmitting to the main hold. Secondly, there exists high-density local modes in the working frequency range of the main engine and thus the local resonance occurs. Thirdly, the abnormal engagement of gears caused by the large deflection of the shaft bearing due to its low mounting rigidity leads to violent extra impulse excitations at high speeds. Then the modification against the dynamic defects is given by simply improving the specific stiffness of the water tanks. And the effect is validated by the FEM calculation. Some important experience is obtained with the problems being solved, which is useful in the design of ships with the same propulsion system. It is also believed that the dynamic consideration is as important as the static analysis for the ships, and that most of the vibration problems may be avoided with a proper acoustic design.
