<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://files.passeidireto.com/04c9e0dc-430a-4112-a131-4e73a2c723b7/bg1.png"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls9 ws2"> </div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 ls9 ws2">1 </div><div class="c x1 y3 w2 h3"><div class="t m0 x0 h2 y4 ff1 fs0 fc0 sc0 ls9 ws2"> </div></div><div class="t m0 x1 h4 y5 ff2 fs1 fc1 sc0 ls9 ws2">Vibrações Mecânicas \u2013 <span class="_0 blank"> </span>Resumo </div><div class="t m0 x1 h4 y6 ff2 fs1 fc1 sc0 ls9 ws2"> </div><div class="t m0 x1 h5 y7 ff3 fs2 fc0 sc0 ls9 ws2">TÉCNICAS DE MEDIÇÃO<span class="fs3 fc2"> </span></div><div class="t m0 x1 h6 y8 ff3 fs3 fc1 sc0 ls9 ws2"> Introdução: </div><div class="t m0 x1 h7 y9 ff2 fs4 fc0 sc0 ls9 ws2">Medir vibrações é importante para vários motivos, entre ele<span class="_1 blank"></span>s: </div><div class="t m0 x3 h7 ya ff2 fs4 fc0 sc0 ls9 ws0">1.<span class="ff4 ls0 ws2"> </span><span class="ws2">Produtividade cada vez mais altas e Projetos Econômicos; </span></div><div class="t m0 x3 h7 yb ff2 fs4 fc0 sc0 ls9 ws0">2.<span class="ff4 ls1 ws2"> </span><span class="ws2">Medição das frequências naturais de uma estrutura ou máqui<span class="_1 blank"></span>nas; </span></div><div class="t m0 x3 h7 yc ff2 fs4 fc0 sc0 ls9 ws0">3.<span class="ff4 ls2 ws2"> </span><span class="ws2">Verificação das condições de projeto; </span></div><div class="t m0 x3 h7 yd ff2 fs4 fc0 sc0 ls9 ws0">4.<span class="ff4 ls3 ws2"> </span><span class="ws2">Verificar se é necessário, ou está adequado, o Is<span class="_1 blank"></span>olamento de Vibrações; </span></div><div class="t m0 x3 h7 ye ff2 fs4 fc0 sc0 ls9 ws0">5.<span class="ff4 ls4 ws2"> </span><span class="ws2">Manutenção Preditiva de máquinas e estruturas; </span></div><div class="t m0 x3 h7 yf ff2 fs4 fc0 sc0 ls9 ws0">6.<span class="ff4 ls5 ws2"> </span><span class="ws2">Entre outros. </span></div><div class="t m0 x1 h6 y10 ff3 fs3 fc1 sc0 ls9 ws2">Técnicas de Medição de Vibrações: </div><div class="t m0 x1 h7 y11 ff2 fs4 fc0 sc0 ls9 ws2">Basicamente temos dois tipos de medidas: </div><div class="t m0 x1 h7 y12 ff2 fs4 fc0 sc0 ls9 ws0">1.<span class="ff4 ls6 ws2"> </span><span class="ws2">Somente de respostas em máquinas operando em condiçõe<span class="_1 blank"></span>s de trabalho: </span></div><div class="t m0 x4 h7 y13 ff2 fs4 fc0 sc0 ls9 ws2">São usados em aplicações de manutenção predit<span class="_1 blank"></span>iva por análise de vibrações ou </div><div class="t m0 x1 h7 y14 ff2 fs4 fc0 sc0 ls9 ws2">em análise modal operacional. </div><div class="t m0 x1 h7 y15 ff2 fs4 fc0 sc0 ls9 ws0">2.<span class="ff4 ls7 ws2"> </span><span class="ws2">Medidas realizadas em ambiente de laboratório: </span></div><div class="t m0 x1 h7 y16 ff2 fs4 fc0 sc0 ls9 ws2">Onde o sinal de excitação é proporcionado por um excitador<span class="_1 blank"></span>. </div><div class="t m0 x4 h7 y17 ff2 fs4 fc0 sc0 ls9 ws2">São <span class="_1 blank"></span>usados, <span class="_2 blank"></span>mais <span class="_2 blank"></span>comumente, <span class="_2 blank"></span>em análi<span class="_1 blank"></span>se <span class="_2 blank"></span>modal experiment<span class="_1 blank"></span>al <span class="_2 blank"></span>e análi<span class="_1 blank"></span>se <span class="_2 blank"></span>dinâmica </div><div class="t m0 x1 h7 y18 ff2 fs4 fc0 sc0 ls9 ws2">visando a modificação estrutural ou em testes de produtos e protóti<span class="_1 blank"></span>pos.<span class="_0 blank"> </span> </div><div class="t m0 x1 h6 y19 ff3 fs3 fc1 sc0 ls9 ws2">Medição de Campo </div><div class="t m0 x1 h7 y1a ff2 fs4 fc0 sc0 ls9 ws2">São medições feitas em equipamentos ou estrut<span class="_1 blank"></span>uras reais em pleno funcionamento, </div><div class="t m0 x1 h7 y1b ff2 fs4 fc0 sc0 ls9 ws2">onde, normalmente, as forças de excitação são desconheci<span class="_1 blank"></span>das.<span class="_0 blank"> </span> </div><div class="t m0 x1 h7 y1c ff2 fs4 fc0 sc0 ls9 ws2">Utilizam-se coletores comerciais que são compostos: </div><div class="t m0 x3 h7 y1d ff5 fs4 fc0 sc0 ls9 ws1">\uf0b7<span class="ff4 ls8 ws2"> <span class="ff2 ls9">Sistema de aquisição com conversor A/D, </span></span></div><div class="t m0 x3 h7 y1e ff5 fs4 fc0 sc0 ls9 ws1">\uf0b7<span class="ff4 ls8 ws2"> <span class="ff2 ls9">Filtro anti-aliasing analógico, </span></span></div><div class="t m0 x3 h7 y1f ff5 fs4 fc0 sc0 ls9 ws1">\uf0b7<span class="ff4 ls8 ws2"> <span class="ff2 ls9">Condicionador de sinais, e </span></span></div></div><div class="pi" data-data='{"ctm":[1.000000,0.000000,0.000000,1.000000,0.000000,0.000000]}'></div></div> <div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://files.passeidireto.com/04c9e0dc-430a-4112-a131-4e73a2c723b7/bg2.png"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls9 ws2"> </div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 ls9 ws2">2 </div><div class="c x1 y3 w2 h3"><div class="t m0 x0 h2 y4 ff1 fs0 fc0 sc0 ls9 ws2"> </div></div><div class="t m0 x3 h7 y20 ff5 fs4 fc0 sc0 ls9 ws1">\uf0b7<span class="ff4 ls8 ws2"> <span class="ff2 ls9">Sensor acoplado. </span></span></div><div class="t m0 x1 h7 y21 ff2 fs4 fc0 sc0 ls9 ws2">Existem aparelhos mais simples (figura <span class="_1 blank"></span>1a) que permitem apenas <span class="_1 blank"></span>a leitura instantânea, </div><div class="t m0 x1 h7 y22 ff2 fs4 fc0 sc0 ls9 ws2">ou seja, <span class="_0 blank"> </span>o valor da <span class="_0 blank"> </span>vibração medida no<span class="_0 blank"> </span> ato. Outros, <span class="_0 blank"> </span>um pouco mais <span class="_0 blank"> </span>sofisticados (figura </div><div class="t m0 x1 h7 y23 ff2 fs4 fc0 sc0 ls9 ws2">1b), <span class="_3 blank"> </span>já <span class="_3 blank"> </span>fazem <span class="_3 blank"> </span>a <span class="_3 blank"> </span>coletada <span class="_3 blank"> </span>de <span class="_3 blank"> </span>diversos <span class="_3 blank"> </span>dados, <span class="_3 blank"> </span>armazenando-os <span class="_3 blank"> </span>permitindo <span class="_3 blank"> </span>o </div><div class="t m0 x1 h7 y24 ff2 fs4 fc0 sc0 ls9 ws2">descarregamento <span class="_4 blank"> </span>posterior <span class="_4 blank"> </span>em <span class="_4 blank"> </span>um <span class="_4 blank"> </span>computador, <span class="_4 blank"> </span>que <span class="_4 blank"> </span>possui <span class="_4 blank"> </span>um <span class="_5 blank"> </span>software <span class="_4 blank"> </span>próprio <span class="_4 blank"> </span>que </div><div class="t m0 x1 h7 y25 ff2 fs4 fc0 sc0 ls9 ws2">proporcionará <span class="_2 blank"></span>a análise <span class="_2 blank"></span>dos <span class="_2 blank"></span>dados. E <span class="_2 blank"></span>por <span class="_2 blank"></span>fim, existem <span class="_2 blank"></span>aparelhos <span class="_2 blank"></span>mais <span class="_1 blank"></span>completos <span class="_2 blank"></span>(figura </div><div class="t m0 x1 h7 y26 ff2 fs4 fc0 sc0 ls9 ws2">1b) <span class="_6 blank"> </span>que <span class="_6 blank"> </span>possuem <span class="_6 blank"> </span>softwares <span class="_6 blank"> </span>analisadores <span class="_6 blank"> </span>de <span class="_6 blank"> </span>sinais <span class="_6 blank"> </span>que <span class="_6 blank"> </span>permitem <span class="_6 blank"> </span>diagnósticos <span class="_6 blank"> </span>no </div><div class="t m0 x1 h7 y27 ff2 fs4 fc0 sc0 ls9 ws2">momento da coleta de dados. Obviamente, os preços tam<span class="_1 blank"></span>bém são diferenciados. </div><div class="t m0 x1 h7 y28 ff2 fs4 fc0 sc0 ls9 ws2">Importante ressaltar que qualquer hardware uti<span class="_1 blank"></span>lizado deve ser calibrado previamente. </div><div class="t m0 x1 h7 y29 ff2 fs4 fc0 sc0 ls9 ws2"> <span class="_7 blank"> </span>(a) <span class="_8 blank"> </span>(b) <span class="_9 blank"> </span>(c) </div><div class="t m0 x5 h8 y2a ff2 fs5 fc0 sc0 ls9 ws2">Figura 1 \u2013 Tipos de Medidores de Vibrações<span class="_0 blank"> </span> </div><div class="t m0 x1 h6 y2b ff3 fs3 fc1 sc0 ls9 ws2">Medição de Laboratorio<span class="fs4"> </span></div><div class="t m0 x1 h7 y2c ff2 fs4 fc0 sc0 ls9 ws2">É <span class="_4 blank"> </span>o <span class="_0 blank"> </span>tipo <span class="_4 blank"> </span>de <span class="_4 blank"> </span>medição <span class="_4 blank"> </span>caracterizado <span class="_0 blank"> </span>pelo <span class="_4 blank"> </span>teste <span class="_4 blank"> </span>em <span class="_0 blank"> </span>ambiente <span class="_4 blank"> </span>controlado. <span class="_4 blank"> </span>São <span class="_0 blank"> </span>utilizados </div><div class="t m0 x1 h7 y2d ff2 fs4 fc0 sc0 ls9 ws2">os mesmos tipos de instrumentos já citados, e mais: </div><div class="t m0 x3 h7 y2e ff5 fs4 fc0 sc0 ls9 ws1">\uf0b7<span class="ff4 ls8 ws2"> <span class="ff2 ls9">Geradores de sinais, </span></span></div><div class="t m0 x3 h7 y2f ff5 fs4 fc0 sc0 ls9 ws1">\uf0b7<span class="ff4 ls8 ws2"> <span class="ff2 ls9">Amplificadores de potência, e, </span></span></div><div class="t m0 x3 h7 y30 ff5 fs4 fc0 sc0 ls9 ws1">\uf0b7<span class="ff4 ls8 ws2"> <span class="ff2 ls9">Um <span class="_3 blank"> </span>excitador <span class="_3 blank"> </span>que <span class="_a blank"> </span>pode <span class="_3 blank"> </span>ser <span class="_3 blank"> </span>eletrodinâmico, <span class="_3 blank"> </span>magnético, <span class="_a blank"> </span>hidráulico <span class="_3 blank"> </span>ou </span></span></div><div class="t m0 x6 h7 y31 ff2 fs4 fc0 sc0 ls9 ws2">piezocerâmico. </div><div class="t m0 x1 h7 y32 ff2 fs4 fc0 sc0 ls9 ws2">Acoplado <span class="_4 blank"> </span>ao <span class="_4 blank"> </span>excitador <span class="_4 blank"> </span>é <span class="_4 blank"> </span>comum <span class="_4 blank"> </span>se <span class="_4 blank"> </span>empregar <span class="_4 blank"> </span>um <span class="_4 blank"> </span>sensor <span class="_5 blank"> </span>de <span class="_4 blank"> </span>força <span class="_4 blank"> </span>composto <span class="_4 blank"> </span>por <span class="_4 blank"> </span>uma </div><div class="t m0 x1 h7 y33 ff2 fs4 fc0 sc0 ls9 ws2">célula de carga que está acoplada a um sistema de aquisição de dados. </div><div class="t m0 x1 h7 y34 ff2 fs4 fc0 sc0 ls9 ws2">Assim podemos estimar FRF\u2019s, IRF\u2019s e extrair parâmetros modais. </div><div class="t m0 x1 h6 y35 ff3 fs3 fc1 sc0 ls9 ws2">Transdutores para Medição de Vibrações </div><div class="t m0 x1 h7 y36 ff2 fs4 fc0 sc0 ls9 ws2">Transdutor <span class="_b blank"> </span>é <span class="_b blank"> </span>um <span class="_b blank"> </span>dispositivo qu<span class="_0 blank"> </span>e <span class="_b blank"> </span>transforma <span class="_b blank"> </span>valores <span class="_b blank"> </span>de <span class="_b blank"> </span>variáveis <span class="_b blank"> </span>físicas <span class="_b blank"> </span>em <span class="_b blank"> </span>sinais </div><div class="t m0 x1 h7 y37 ff2 fs4 fc0 sc0 ls9 ws2">elétricos <span class="_0 blank"> </span>equivalentes. <span class="_0 blank"> </span>O <span class="_0 blank"> </span>transdutor <span class="_0 blank"> </span>de <span class="_0 blank"> </span>vibrações <span class="_0 blank"> </span>mede <span class="_0 blank"> </span>o <span class="_0 blank"> </span>deslocamento <span class="_0 blank"> </span>relativo <span class="_0 blank"> </span>entre </div><div class="t m0 x1 h7 y38 ff2 fs4 fc0 sc0 ls9 ws2">duas coordenadas. </div><div class="t m0 x1 h7 y39 ff2 fs4 fc0 sc0 ls9 ws2">Sabendo que: </div></div><div class="pi" data-data='{"ctm":[1.000000,0.000000,0.000000,1.000000,0.000000,0.000000]}'></div></div> <div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img fetchpriority="low" loading="lazy" class="bi x0 y0 w1 h1" alt="" src="https://files.passeidireto.com/04c9e0dc-430a-4112-a131-4e73a2c723b7/bg3.png"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls9 ws2"> </div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 ls9 ws2">3 </div><div class="c x1 y3 w2 h3"><div class="t m0 x0 h2 y4 ff1 fs0 fc0 sc0 ls9 ws2"> </div></div><div class="t m0 x7 h9 y3a ff6 fs4 fc0 sc0 ls9 ws3">\ue756<span class="_1 blank"></span>\u0308 =<span class="_c blank"> </span>\ue754<span class="_d blank"></span>\u0308 \u2212<span class="_b blank"> </span>\ue755<span class="_e blank"></span>\u0308<span class="_f blank"> </span><span class="ff2 ws2">, e </span></div><div class="t m0 x3 h9 y3b ff6 fs4 fc0 sc0 ls9 ws4">\ue749\ue754<span class="_d blank"></span>\u0308<span class="_10 blank"> </span>=<span class="_c blank"> </span>\ue728</div><div class="t m0 x8 ha y3c ff6 fs6 fc0 sc0 ls9 ws5">\uebe0\uebe2\uebdf\uebd4 <span class="fs4 ws6 v1">\u2212 \ue728</span></div><div class="t m0 x9 hb y3c ff6 fs6 fc0 sc0 ls9 ws7">\uebd4\uebe0\uebe2\uebe5\uebe7 <span class="ff2 fs7 fc3 lsa ws2 v1"> </span><span class="ff7 fs4 lsb v1">\uf0e0<span class="ff2 ls9 ws2"> <span class="ff6">\ue749\ue754<span class="_d blank"></span>\u0308<span class="_f blank"> </span> \u2212 \ue747\ue754<span class="_6 blank"> </span>+<span class="_b blank"> </span>\ue747\ue755<span class="_6 blank"> </span>\u2212 \ue73f<span class="_4 blank"> </span>\ue754<span class="_e blank"></span>\u0307<span class="_11 blank"> </span>+ \ue73f<span class="_0 blank"> </span>\ue755<span class="_e blank"></span>\u0307<span class="_f blank"> </span><span class="ff2 fs7 fc3 lsa"> </span><span class="ff7 lsb">\uf0e0</span><span class="ff2"> </span><span class="ws4">\ue749 \ue756\u0308<span class="_6 blank"> </span>+<span class="_b blank"> </span>\ue73f<span class="_0 blank"> </span>\ue756\u0307<span class="_6 blank"> </span>+<span class="_b blank"> </span>\ue747\ue756<span class="_12 blank"> </span>=<span class="_c blank"> </span>\u2212\ue749\ue755<span class="_d blank"></span>\u0308<span class="_f blank"> </span><span class="ff2 ws2"> </span></span></span></span></span></div><div class="t m0 x1 hc y3d ff2 fs4 fc0 sc0 ls9 ws2">Para <span class="_4 blank"> </span>sinais <span class="_0 blank"> </span>harmônicos <span class="_4 blank"> </span>do <span class="_4 blank"> </span>tipo <span class="_4 blank"> </span><span class="ff6 lsb">y<span class="ls9 ws8 v2">(</span><span class="lsa">t<span class="lsc v2">)</span><span class="ls9 ws9">=<span class="_c blank"> </span>Y. sen(\ue7f1. \ue750<span class="_0 blank"> </span>)</span></span></span> <span class="_4 blank"> </span>e <span class="_4 blank"> </span>fazendo <span class="_0 blank"> </span>a <span class="_4 blank"> </span>derivada <span class="_4 blank"> </span>de <span class="_0 blank"> </span>primeira <span class="_4 blank"> </span>e </div><div class="t m0 x1 h7 y3e ff2 fs4 fc0 sc0 ls9 ws2">segunda ordem, temos: </div><div class="t m0 xa hd y3f ff6 fs4 fc0 sc0 ls9 wsa">\ue755<span class="_e blank"></span>\u0308 <span class="ws8 v2">(</span><span class="lsd">\ue750<span class="lse v2">)</span></span><span class="wsb">=<span class="_c blank"> </span>Y.<span class="_13 blank"> </span>\ue7f1<span class="fs6 lsf v3">\ueb36</span><span class="wsc">. sen<span class="_0 blank"> </span>(\ue7f1. \ue750<span class="_4 blank"> </span>)<span class="ff2 ws2"> </span></span></span></div><div class="t m0 x1 h7 y40 ff2 fs4 fc0 sc0 ls9 ws2">Assim, podemos escrever: </div><div class="t m0 xb hd y41 ff6 fs4 fc0 sc0 ls9 ws4">\ue749\ue756\u0308<span class="_6 blank"> </span>+<span class="_b blank"> </span>\ue73f<span class="_0 blank"> </span>\ue756\u0307<span class="_6 blank"> </span>+<span class="_b blank"> </span>\ue747\ue756<span class="_12 blank"> </span>=<span class="_c blank"> </span>\u2212\ue749 .<span class="_13 blank"> </span>Y.<span class="_13 blank"> </span>\ue7f1 <span class="fs6 lsf v3">\ueb36</span><span class="wsc">. sen(\ue7f1<span class="_0 blank"> </span>. \ue750<span class="_0 blank"> </span>)<span class="ff2 ws2"> </span></span></div><div class="t m0 x1 h7 y42 ff2 fs4 fc0 sc0 ls9 ws2">Então: </div><div class="t m0 xc he y43 ff6 fs4 fc0 sc0 lsb">y<span class="ls9 ws8 v2">(</span><span class="lsa">t<span class="lsc v2">)</span><span class="ls10">=<span class="fs6 ls9 wsd v4">\uebbf .\uebde<span class="_0 blank"> </span>.\ueb71\ueb63\ueb6c(\uec20 .\uebe7<span class="_0 blank"> </span>\ueb3f\u2205)<span class="ff2 ws2"> </span></span></span></span></div><div class="t m0 xd hf y44 ff6 fs6 fc0 sc0 ls9 wse">\ueda5<span class="ls11 v0">(</span><span class="wsf v0">\ueb35\ueb3f\uebe5 <span class="fs8 ls12 v1">\uec2e</span><span class="ls11 v2">)</span><span class="fs8 ls13 v1">\uec2e</span><span class="wse">\ueb3e<span class="ls11 v2">(</span><span class="ws10">\ueb36.\uec15.\uebe5 <span class="ls11 v2">)</span><span class="fs8 ls14 v1">\uec2e</span><span class="ff2 fs4 ws2 v5">, <span class="ff6 lsb ws11">tan<span class="ls9 ws8 v2">(</span><span class="lsa">\u2205<span class="ls15 v2">)</span><span class="ls16">=</span></span></span></span><span class="ws12 v6">\ueb36.\uec15 .\uebe5</span></span></span></span></div><div class="t m0 xe h10 y45 ff6 fs6 fc0 sc0 ls9 wsf">\ueb35\ueb3f\uebe5 <span class="fs8 ls13 v1">\uec2e</span><span class="ff2 fs4 ws2 v7"> e <span class="ff6 ws8">z<span class="v2">(</span><span class="lsa">t<span class="lsc v2">)</span><span class="ls17">=</span></span></span></span><span class="ws13 v8">\uebe0.\uebec.\uec20<span class="_0 blank"> </span></span><span class="fs8 ls12 v9">\uec2e</span><span class="ws14 v8">.\ueb71\ueb63\ueb6c(\uec20.\uebe7<span class="_0 blank"> </span>\ueb3f\u2205)<span class="ff2 ws2"> </span></span></div><div class="t m0 xf h11 y46 ff6 fs6 fc0 sc0 ls18">\uebde<span class="ls9 wse v0">\ueda5<span class="ls11 v0">(</span></span><span class="ls9 wsf">\ueb35\ueb3f\uebe5 <span class="fs8 ls12 v1">\uec2e</span><span class="wse v2">)</span><span class="fs8 ls12 v1">\uec2e</span><span class="wse">\ueb3e<span class="v2">(</span><span class="ws10">\ueb36.\uec15.\uebe5 <span class="ls11 v2">)</span><span class="fs8 ls13 v1">\uec2e</span><span class="ff2 fs4 ws2 v5"> </span></span></span></span></div><div class="t m0 x1 h7 y47 ff2 fs4 fc0 sc0 ls9 ws2">Assim a razão entre as duas amplitudes z e y é dado por: </div><div class="t m0 x10 h9 y48 ff6 fs4 fc0 sc0 ls9">\ue756</div><div class="t m0 x10 h12 y49 ff6 fs4 fc0 sc0 ls19">\ue755<span class="ls1a va">=</span><span class="ls1b vb">\ue74e</span><span class="fs6 lsf vc">\ueb36</span><span class="ff2 ls9 ws2 vb"> </span></div><div class="t m0 x11 h13 y4a ff6 fs4 fc0 sc0 lsa">\ueda5<span class="ls9 ws8 v2">(</span><span class="ls9 ws15 v0">1<span class="_b blank"> </span>\u2212<span class="_b blank"> </span>\ue74e <span class="fs6 ls1c vd">\ueb36</span><span class="ws8 v2">)</span><span class="fs6 ls1d vd">\ueb36</span><span class="ls1e">+</span><span class="ws8 v2">(</span><span class="wsc">2. \ue7e6<span class="_0 blank"> </span>. \ue74e<span class="_0 blank"> </span><span class="ws8 v2">)</span><span class="fs6 lsf vd">\ueb36</span><span class="ff2 ws2 ve"> </span></span></span></div><div class="t m0 x1 h7 y4b ff2 fs4 fc0 sc0 ls9 ws2">Basicamente, temos dois tipos de transdutores de vibrações: </div><div class="t m0 x3 h7 y4c ff4 fs4 fc0 sc0 ls9 ws2">\u2022 <span class="_14 blank"> </span><span class="ff2">Baixa Frequência: </span></div><div class="t m0 x4 he y4d ff2 fs4 fc0 sc0 ls9 ws2">Sua principal característica é <span class="_6 blank"> </span><span class="ff6 fs6 v4">\uec20</span></div><div class="t m0 x12 h14 y4e ff6 fs6 fc0 sc0 ls9 wse">\uec20<span class="fs8 ls1f vf">\uecd9</span><span class="fs4 ws16 v7">\u226b 1<span class="ff2 ws2">, isso quer dizer <span class="_0 blank"> </span>que a frequência do <span class="_0 blank"> </span>sistema </span></span></div><div class="t m0 x4 h7 y4f ff2 fs4 fc0 sc0 ls9 ws2">a <span class="_15 blank"> </span>ser <span class="_15 blank"> </span>medido <span class="_15 blank"> </span>é <span class="_15 blank"> </span>muito <span class="_15 blank"> </span>maior <span class="_15 blank"> </span>do <span class="_15 blank"> </span>que <span class="_15 blank"> </span>a <span class="_15 blank"> </span>frequência <span class="_15 blank"> </span>natural <span class="_15 blank"> </span>do <span class="_15 blank"> </span>transdutor, </div><div class="t m0 x4 h7 y50 ff2 fs4 fc0 sc0 ls9 ws2">consequentemente, <span class="_0 blank"> </span>z<span class="ff8"> <span class="_4 blank"> </span>\u2248 <span class="_0 blank"> </span>y, <span class="_0 blank"> </span></span>ou <span class="_4 blank"> </span>seja, <span class="_0 blank"> </span>a <span class="_4 blank"> </span>amplitude Z <span class="_4 blank"> </span>do <span class="_0 blank"> </span>transdutor <span class="_4 blank"> </span>é, praticame<span class="_0 blank"> </span>nte, </div><div class="t m0 x4 h7 y51 ff2 fs4 fc0 sc0 ls9 ws2">a mesma do sistema medido. </div><div class="t m0 x4 h7 y52 ff2 fs4 fc0 sc0 ls9 ws2">Os mais comuns são os <span class="fc1 ws0">Vibrômetros<span class="ff3 ws2"> </span></span><span class="lsa">e</span><span class="ff3 fc1"> <span class="ff2 ws0">Sismômetros</span><span class="fc2 ws17">.</span></span> </div><div class="t m0 x3 h7 y53 ff4 fs4 fc0 sc0 ls9 ws2">\u2022 <span class="_14 blank"> </span><span class="ff2">Alta Frequência: </span></div><div class="t m0 x4 h7 y54 ff2 fs4 fc0 sc0 ls9 ws2">Os mais usados são os <span class="fc1 ws0">Acelerômetros</span><span class="ff3">. </span></div><div class="t m0 x4 h7 y55 ff2 fs4 fc0 sc0 ls9 ws2">Basicamente <span class="_4 blank"> </span>são<span class="_0 blank"> </span> <span class="_5 blank"> </span>compostos <span class="_5 blank"> </span>de <span class="_5 blank"> </span>uma <span class="_4 blank"> </span>peq<span class="_0 blank"> </span>uena <span class="_4 blank"> </span>massa <span class="_5 blank"> </span>sobre <span class="_5 blank"> </span>uma <span class="_5 blank"> </span>base <span class="_5 blank"> </span>com <span class="_5 blank"> </span>dois </div><div class="t m0 x4 h7 y56 ff2 fs4 fc0 sc0 ls9 ws2">cristais <span class="_c blank"> </span>piezelétricos, <span class="_12 blank"> </span>um <span class="_c blank"> </span>acoplado <span class="_12 blank"> </span>na <span class="_c blank"> </span>massa <span class="_12 blank"> </span>e <span class="_12 blank"> </span>outro <span class="_c blank"> </span>acoplado <span class="_12 blank"> </span>na <span class="_c blank"> </span>base. <span class="_12 blank"> </span>O </div><div class="t m0 x4 h7 y57 ff2 fs4 fc0 sc0 ls9 ws2">movimento <span class="_16 blank"> </span>relativo <span class="_16 blank"> </span>dos <span class="_16 blank"> </span>cristais <span class="_16 blank"> </span>gera <span class="_16 blank"> </span>uma <span class="_16 blank"> </span>tensão <span class="_16 blank"> </span>que <span class="_16 blank"> </span>é <span class="_16 blank"> </span>enviada <span class="_16 blank"> </span>a <span class="_16 blank"> </span>um </div><div class="t m0 x4 h7 y58 ff2 fs4 fc0 sc0 ls9 ws2">condicionador de sinais e depois para o sistema de aquisição. </div><div class="t m0 x1 h6 y59 ff3 fs3 fc1 sc0 ls9 ws2">Exercício Resolvido </div><div class="t m0 x1 h7 y5a ff2 fs4 fc0 sc0 ls9 ws2">Um <span class="_2 blank"></span>transdutor com <span class="_2 blank"></span><span class="ff5">\uf077</span></div><div class="t m0 x13 h15 y5b ff2 fs9 fc0 sc0 ls9 ws18">n<span class="fs4 ws2 v10">= <span class="_2 blank"></span>1 Hz <span class="_2 blank"></span>é <span class="_2 blank"></span>usado para <span class="_2 blank"></span>medir <span class="_2 blank"></span>uma vib<span class="_1 blank"></span>ração <span class="_2 blank"></span>de <span class="ff5 ws1">\uf077</span> <span class="_2 blank"></span>= <span class="_2 blank"></span>4 Hz; <span class="_2 blank"></span>A <span class="_1 blank"></span>amplitude </span></div><div class="t m0 x1 h7 y5c ff2 fs4 fc0 sc0 ls9 ws2">indicada pelo transdutor é de 1,3 mm, qual a ampli<span class="_1 blank"></span>tude correta? (\u03be=0). </div><div class="t m0 x1 h7 y5d ff2 fs4 fc0 sc0 ls9 ws2">Resolução: </div><div class="t m0 x1 he y5e ff2 fs4 fc0 sc0 ls9 ws2">Calculando a razão de frequências: <span class="ff6 ws19">\ue74e =<span class="_17 blank"> </span><span class="fs6 v4">\uec20</span></span></div><div class="t m0 x14 h16 y5f ff6 fs6 fc0 sc0 ls9 wse">\uec20<span class="fs8 ls1f vf">\uecd9</span><span class="fs4 ls20 v7">=</span><span class="v8">\ueb38</span></div><div class="t m0 x15 h14 y5f ff6 fs6 fc0 sc0 ls21">\ueb35<span class="fs4 ls9 ws1a v7">= 4<span class="ff8 ws2"> </span></span></div><div class="t m0 x1 h7 y60 ff2 fs4 fc0 sc0 ls9 ws2">Temos um transdutor de alta frequência. </div></div><div class="pi" data-data='{"ctm":[1.000000,0.000000,0.000000,1.000000,0.000000,0.000000]}'></div></div> <div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img fetchpriority="low" loading="lazy" class="bi x0 y0 w1 h1" alt="" src="https://files.passeidireto.com/04c9e0dc-430a-4112-a131-4e73a2c723b7/bg4.png"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls9 ws2"> </div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 ls9 ws2">4 </div><div class="c x1 y3 w2 h3"><div class="t m0 x0 h2 y4 ff1 fs0 fc0 sc0 ls9 ws2"> </div></div><div class="t m0 x1 h7 y3a ff2 fs4 fc0 sc0 ls9 ws2">Assim: </div><div class="t m0 x16 h9 y61 ff6 fs4 fc0 sc0 ls9">\ue756</div><div class="t m0 x16 h17 y62 ff6 fs4 fc0 sc0 ls22">\ue755<span class="ls9 ws2 va">=<span class="_c blank"> </span> <span class="_13 blank"> </span></span><span class="ls9 ws8 vb">1,3</span></div><div class="t m0 xa h12 y62 ff6 fs4 fc0 sc0 ls23">\ue755<span class="ls24 va">=</span><span class="ls1b vb">\ue74e</span><span class="fs6 ls9 vc">\ueb36</span></div><div class="t m0 x17 h18 y63 ff6 fs4 fc0 sc0 ls9 ws8">|<span class="ws15 v11">1<span class="_b blank"> </span>\u2212<span class="_b blank"> </span>\ue74e </span><span class="fs6 lsf v12">\ueb36</span><span class="ls25">|</span><span class="ws2 v13">\u2192<span class="_c blank"> </span>\ue755<span class="_c blank"> </span>=<span class="_c blank"> </span>1,22 (\ue749\ue749<span class="_0 blank"> </span>)<span class="ff2"> </span></span></div><div class="t m0 x1 h7 y64 ff2 fs4 fc0 sc0 ls9 ws2">Chegando ao resultado desejado. </div><div class="t m0 x1 h2 y65 ff1 fs0 fc0 sc0 ls9 ws2"> </div><div class="t m0 x1 h2 y66 ff1 fs0 fc0 sc0 ls9 ws2"> </div></div><div class="pi" data-data='{"ctm":[1.000000,0.000000,0.000000,1.000000,0.000000,0.000000]}'></div></div>
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