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基于修正模态应变能指标的板结构损伤定位
损伤定位 板结构 模态应变能 抗噪性
2019/3/11
为解决模态应变能方法识别中产生的"邻近效应"问题，提出基于修正模态应变能指标的板结构损伤定位方法.该方法首先利用邻近测点的应变能变化相对大小计算权重系数，再根据权重系数对测点相应区域的应变能进行重新分配.此外，通过定义的损伤辨识度指标研究噪声对损伤定位结果的影响.为验证本文所提方法的可行性和有效性，以一个四边简支板为数值算例.算例结果表明，本文方法对于点状、块状和带状损伤都可以实现准确定位，且具有...
The impact of noise at work
noise at work
2014/4/25
Exposure to noise at work can harm workers’ health. The most well-known effect of noise at work is loss of hearing, a problem observed among coppersmiths in 1731. However, it can also exacerbate stres...
大冶铁矿球团鼓风机房噪声控制治理
2007/12/25
摘要主要介绍了大冶铁矿球团厂竖炉鼓风机房噪声治理的过程，其中包括噪声的诊断分析，控制治理方案，设计特点以及治理前后的情况对比和需要进一步完善的地方。
有限长圆柱壳中振动功率流的输入与传播
圆柱壳 振动 功率流
2007/8/10
以一有限长弹性圆柱壳受迫振动的功率流为研究对象，用Flügge方程和Hamilton变分原理推导了壳体的运动方程，获得了壳体在某一点受简谐外载作用下的响应。利用功率流的基本定义，研究了当壳体受迫振动时输入结构的功率流和壳体中各内力所携带功率流沿轴向方向传播时的变化规律，旨在为工程中类似结构的减振降噪提供指导性原则。研究结果表明，输入功率流与传播功率流随频率的变化规律在壳体环频率附近存在着一些差异；...
工业企业厂界噪声测量方法GB12348-1990
2007/8/3
1 名词术语1.1 A声级
用A计权网络测得的声级，用LA表示，单位dB(A)
1.2 等效声级
在某规定时间内A声级的能量平均值，又称等效连续A声级，用Leq表示，单位为dB(A)。
按此定义此量为
1 T
Led=10Ig（─ ∫ 10(0.1LA)ｄt） ...........(1)
T 0
式中：LA──t时刻的瞬时A声级；
T──规定的测量时间。
当测量是采样测量...
工业企业厂界噪声标准GB12348-1990
2007/8/3
1 标准的适用范围
本标准适用于工厂及有可能造成噪声污染的企事业单位的边界。
1.1 标准值
各类厂界噪声标准值列于下表：
等效声级Leq［dB(A)］
类别昼间夜间Ⅰ5545Ⅱ6050Ⅲ6060Ⅳ70551.2 各类标准适用范围的划定
1.2.1 Ⅰ类标准适用于以居住、文教机关为主的区域。
1.2.2 Ⅱ类标准适用于居住、商业、工业混杂区及商业中心区
1.2.3 Ⅲ类标准...
Noise in figures
Noise in figures
2014/4/25
This report is the first in a series of risk observatory thematic reports dedicated to a specific risk, sector or group of workers. It sets out to describe the situation in Europe as regards exposure ...
advice for young workers
advice young workers
2014/4/25
One of the most significant risks that you face as a young worker is noise. Many workplaces expose you to high levels of noise for prolonged periods, which can cause permanent damage to your hearing, ...
Report - Noise in figures
Noise figures
2014/4/25
A growing proportion of workers are employed in the service sector. This is why this report not only includes information for the traditionally well-known noise-exposed sectors such as construction, m...
Prevention of risks from occupational noise in practice
risks occupational noise in practice
2014/4/25
This publication contains real examples of how enterprises and organisations from across the European Union have taken a variety of actions to reduce the exposure of workers to noise. The cases should...
Every day, millions of employees in Europe are exposed to noise at work and all the risks this can entail. While noise is most obviously a problem in industries such as metal manufacturing and constru...
Every day, millions of employees in Europe are exposed to noise at work and all the risks this can entail. For European Week for Safety and Health 2005, the Agency has produced a report looking at how...
Noise at work
Noise at work
2014/4/25
The need to ‘stop that noise’ is evident. Millions of Europe’s workers suffer from work-related hearing difficulties. Noise-induced hearing loss is amongst the most commonly reported occupational dise...
Every day, millions of employees in Europe are exposed to noise at work and all the risks this can entail. While noise is most obviously a problem in industries such as manufacturing and construction,...
Eliminating or reducing excessive noise at work is not simply a legal responsibility for employers; it is also in an organisation’s commercial interests. The safer and healthier the working environmen...