Adams Machinery Gear Model
(4)声学辐射
Tip relieving crowning
no crowning and relieving
with crowning and relieving
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21
齿轮噪声
FFT
通过冠状齿轮和齿轮 修正，啮合力减小了
Time domain simulation SPL (time domain)
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18
Engine Slap Sound Analysis
• Engine Slap Sound Analysis
– The Sound from contact between Cylinder inner wall and Moving Piston
– – – The geometries might be (slightly) different The mesh sizes can be very different (no loss of information from FEA) The penalty on the solver performance is weak Actran
– The results (velocities or displacements) are used as the excitation of the acoustic radiation problem solved by Actran
1m2 0
* P.T. = Power Train
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16
Selective Power Evaluation
• Multiple surfaces can be created in order to measure the power radiated by each part of the power train.
9
声学模型建立
• 声学网格准备
– 振动体包络面: surface wrap mesh of the vibrating structure, for mapping the structure vibration to the acoustic mesh. Boundary Condition Mesh, or BC_MESH – 外部面网格：Exterior infinite elements surface: a convex shape – 体网格： Volume elements between the two surfaces
11
Problem
• This project: a complete truck powertrain, length around 2.5 meters
– The structure vibration is computed with a structural tool
• The Nastran, Abaqus and Ansys files are read by Actran • Some automatic procedures are available with Nastran
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与电磁软件联合仿真
电磁软件
Actran
Compute the 3D magnetic field
Load structural model with electromagnetic forces
Compute radiated noise
Pressure at microphones Radiated power Contributions analysis
12
Computation Procedure
Structure Computation Actran Model (w/ ground)
Actran Results
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13
Structural Results Mapping
• • BC_MESH: map the structure results on the acoustic surface Procedure used: based on integration ( more advanced technology than interpolation )
FEM MODEL （Elastic）
Force due to contact
Kinematic behavior
axial load due to kinematic motion
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Adams model
19
Engine Slap Sound Analysis
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5
频率域仿真 和 时间域仿真
• 频率域仿真： 针对不随时间变化的现象，线性问题，计算频率响应函数和传 递函数
• 时间域仿真，瞬态仿真： 可针对瞬态随时间变化现象，非线性声学激励，发动机（动力 总成）加速过程，冲击，碰撞现象等
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7
动力装置噪声辐射问题
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8
声辐射仿真流程
1. 振动计算：MSC Nastran, Adams/Flex, Marc, Actran, etc. Structure surface vibration 2. 声学计算: Actran in Frequency or Time Domain
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机械行业噪声问题
动力装置
Gear Box Engine Compressor Pump
进气，排气 车辆机械驾驶舱
Intake
噪声
Exhaust
旋转器械：风扇，涡轮增压器，压缩机等
Cooling Fan Turbocharger HVAC
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– From Adams/Flex coupling analysis, motion and vibration is simulated
• as a sound source, the vibration response of the crank case surface can be obtained.
Time - Frequency - Pressure Map
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20
齿轮噪声
• 目标
– 实际机床的齿轮噪声
(1)啮合力
• 挑战
– 减小噪声
(2)轴承力
(3)箱体振动
• 解决方法Solution
冠状齿轮和齿形修正
使用Adams模拟多体运动， 使用Actran预测噪声
Adams( Time domain )
Time domain Radiation
Adams
Adams to Actran Toolkit Time domain simulation Adams Standard output Convert from Adams output to OP2
Actran
3. Post Processing and Analysis: Actran Maps FRF Waterfall Elements contribution
Acoustic directivity
Animation
Time domain pressure
Sound file
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声学仿真及在工程中的应用
周泽 声学仿真业务发展经理
2015年5月27日
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1
Actran 软件及技术特点介绍
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2
Actran软件模块
Actran主要模块
• • • 声学 振动声学 气动声学
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Adams与Actran联合： Adams 2 Actran 转换器
• Analysis Flow
– Transient Response Analysis by Adams – Load on each node with a time history is transformed to OP2 file – Radiation analysis on the acoustic space in Actran model
• due to kinematic motion, the contact position changes from time to time • contact force will course crank case vibration • The contact position, forces various with engine rotational speed change
Slides extracted from Experimental Validation of an Efficient Procedure for Large Acoustic Radiation Problems, Gustafsson et.al., ISMA 2010