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噪声与振动控制技术主讲:盛美萍•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity西北工业大学精品课程专业核心课程振动与噪声控制技术本讲内容•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity阻尼作用及产生机理阻尼材料与阻尼结构•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity阻尼作用及产生机理弹性结构内阻尼的定义•阻尼的作用能量损耗nnnEE•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity阻尼产生机理1,工程材料内阻尼2,流体的粘滞阻尼3,结合面阻尼与库仑摩擦阻尼4,冲击阻尼5,磁电效应阻尼•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity工程材料内阻尼产生机理•在应力作用下分子或晶体之间产生相对运动、滑移,消耗能量。BOCDA应变应力P•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity流体的粘滞阻尼产生机理结构和流体接触表面产生能量损耗。无粘流体粘滞流体•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity结合面阻尼与库仑摩擦阻尼产生机理零件表面接触并承受动态载荷,产生阻尼。OO’BCPC’B’P’•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity冲击阻尼产生机理通过附加冲击块,将主系统振动能量转换成冲击块的振动能量。•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity磁电效应阻尼产生机理机械能转换成电能的过程中,由磁电效应产生阻尼。磁极金属导磁片•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity阻尼材料与阻尼结构阻尼材料1,粘弹性阻尼材料2,阻尼涂料3,沥青型阻尼材料4,复合型阻尼金属板材5,阻尼合金6,其它•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity粘弹性阻尼材料•分类:橡胶类、塑料类•特性:随温度变化,随频率变化•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity粘弹性阻尼材料随温度变化特性•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity粘弹性阻尼材料随频率变化特性•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity粘弹性阻尼材料耗能综合特性•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity阻尼涂料•组成:高分子树脂等•用途:飞机、船舶、车辆、各种机械•涂刷注意点:多次涂刷、干透再刷。•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity沥青型阻尼材料•用途:汽车等•分类:熔融型、热熔型、自黏型、磁性型。•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity复合型阻尼金属板材•构成:两块金属板之间夹以粘弹性高分子材料•用途:汽车、飞机、潜艇、电机、风机等。•特点:衰减性好、耐热性好、机械性好、焊接性好、阻燃性等好。•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity阻尼合金类别应用实例大型结构铁路桥梁下部隔声板;钢铁厂装、卸料机内衬、漏斗、溜槽内衬建筑部门高层建筑钢制楼梯、垃圾井筒、钢门、铜制家俱、空调用钢制品交通部门汽车发动机、发动机旋转部件、翻斗车料槽、船舶、飞机等构件—般工厂传递、运输机械构件、铲车料槽、凿岩机内衬、电动机机壳、空气机机壳音响设备音响设备底盘、框架、办公用机械噪声控制设备各种机器隔声罩、大型消声器钢板结构其它记录机机身、激光装置防振台•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity其它阻尼材料•玻璃状阻尼陶瓷•抗静电阻尼材料•抗冲击隔热阻尼材料•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity阻尼基本结构•分类:•离散型的阻尼器件•附加型的阻尼结构•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity离散型的阻尼器件•分类:•减振器(隔振器)•吸振器•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity附加型的阻尼结构•分类:•直接黏附的阻尼结构•(自由层阻尼、约束层阻尼)•(多层约束阻尼、插条式阻尼)•直接附加固定的阻尼结构•(封沙阻尼、空气挤压薄膜阻尼)•直接固定组合的阻尼结构•(结合面阻尼)•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity自由层阻尼H2H1H21基本弹性层阻尼层•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity自由层阻尼计算)465(1)463(22hhehhhehs•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity自由层阻尼提高阻尼效果•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity具有隔离层的自由阻尼•隔离层的作用:放大变形H2H1H31基本弹性层阻尼层H3隔离层(扩变层)•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity约束层阻尼H2H1H31基本弹性层约束层H3阻尼层•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity典型的约束层阻尼结构•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity约束层阻尼的阻尼效果•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity本讲基本要求•了解常用阻尼分类及其产生机理•自由层阻尼效果分析•约束层阻尼效果分析•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity实验预告•混响时间与结构阻尼测试•Prof.ShengMeiping•NorthwesternPolytechnicalUniversity
本文标题:53阻尼作用及产生机理阻尼材料与阻尼结构
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