{"id":62636,"date":"2022-10-15T00:33:24","date_gmt":"2022-10-15T05:33:24","guid":{"rendered":"https:\/\/www.bjultrasonic.com\/the-frequency-limit-of-a-piezoceramic-sheet-and-some-properties\/"},"modified":"2025-01-27T06:15:14","modified_gmt":"2025-01-27T11:15:14","slug":"the-frequency-limit-of-a-piezoceramic-sheet-and-some-properties","status":"publish","type":"post","link":"https:\/\/www.bjultrasonic.com\/cs\/the-frequency-limit-of-a-piezoceramic-sheet-and-some-properties\/","title":{"rendered":"Frekven\u010dn\u00ed limit piezoelektrick\u00e9 desti\u010dky a jej\u00ed vlastnosti"},"content":{"rendered":"<p>Piezoelektrick\u00e9 desti\u010dky nach\u00e1zej\u00ed \u0161irok\u00e9 uplatn\u011bn\u00ed v mnoha oblastech, od ultrazvukov\u00fdch senzor\u016f a aktu\u00e1tor\u016f po precizn\u00ed polohovac\u00ed syst\u00e9my.  Kl\u00ed\u010dov\u00fdm parametrem ovliv\u0148uj\u00edc\u00edm jejich funk\u010dnost je v\u0161ak frekven\u010dn\u00ed limit, kter\u00fd ur\u010duje horn\u00ed hranici efektivn\u00edho provozu.  Tento \u010dl\u00e1nek se podrobn\u011bji zam\u011b\u0159\u00ed na frekven\u010dn\u00ed limit piezoelektrick\u00fdch desek a n\u011bkter\u00e9 d\u016fle\u017eit\u00e9 vlastnosti, kter\u00e9 jej ovliv\u0148uj\u00ed.<\/p>\n<p>Mechanick\u00e9 vlastnosti a rezonan\u010dn\u00ed frekvence<\/p>\n<p>Frekven\u010dn\u00ed limit piezoelektrick\u00e9 desti\u010dky je \u00fazce spjat s jej\u00edmi mechanick\u00fdmi vlastnostmi, zejm\u00e9na s rychlost\u00ed \u0161\u00ed\u0159en\u00ed vln a rozm\u011bry.  Desti\u010dka rezonuje na ur\u010dit\u00fdch frekvenc\u00edch, kter\u00e9 odpov\u00eddaj\u00ed jej\u00edm vlastn\u00edm mod\u016fm kmit\u00e1n\u00ed.  Nejni\u017e\u0161\u00ed z t\u011bchto frekvenc\u00ed, tzv. rezonan\u010dn\u00ed frekvence, je obvykle dominantn\u00ed a ur\u010duje horn\u00ed hranici efektivn\u00edho provozu.  Tato frekvence z\u00e1vis\u00ed na tlou\u0161\u0165ce, d\u00e9lce a \u0161\u00ed\u0159ce desti\u010dky,  a materi\u00e1lov\u00fdch konstant\u00e1ch, jako je Young\u016fv modul a hustota materi\u00e1lu.  Ten\u010d\u00ed desti\u010dky maj\u00ed vy\u0161\u0161\u00ed rezonan\u010dn\u00ed frekvenci, zat\u00edmco tlust\u0161\u00ed desti\u010dky rezonuj\u00ed na ni\u017e\u0161\u00edch frekvenc\u00edch.  Tento vztah je pops\u00e1n n\u00e1sleduj\u00edc\u00ed tabulkou (hodnoty jsou ilustrativn\u00ed a z\u00e1vis\u00ed na konkr\u00e9tn\u00edm materi\u00e1lu a geometrii):<\/p>\n<table class=\"table table-striped table-bordered\">\n<thead>\n<tr>\n<th>Tlou\u0161\u0165ka (mm)<\/th>\n<th>D\u00e9lka (mm)<\/th>\n<th>\u0160\u00ed\u0159ka (mm)<\/th>\n<th>P\u0159ibli\u017en\u00e1 rezonan\u010dn\u00ed frekvence (kHz)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>0.2<\/td>\n<td>20<\/td>\n<td>10<\/td>\n<td>1000<\/td>\n<\/tr>\n<tr>\n<td>0.5<\/td>\n<td>20<\/td>\n<td>10<\/td>\n<td>400<\/td>\n<\/tr>\n<tr>\n<td>1.0<\/td>\n<td>20<\/td>\n<td>10<\/td>\n<td>200<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Elektromechanick\u00e9 vlastnosti a \u00fa\u010dinnost<\/p>\n<p>Krom\u011b mechanick\u00fdch vlastnost\u00ed hraj\u00ed d\u016fle\u017eitou roli tak\u00e9 elektromechanick\u00e9 vlastnosti piezoelektrick\u00e9ho materi\u00e1lu.  Piezoelektrick\u00fd koeficient, kter\u00fd ud\u00e1v\u00e1 vztah mezi mechanick\u00fdm nam\u00e1h\u00e1n\u00edm a elektrick\u00fdm polem, p\u0159\u00edmo ovliv\u0148uje \u00fa\u010dinnost p\u0159em\u011bny energie.  S rostouc\u00ed frekvenc\u00ed se m\u016f\u017ee \u00fa\u010dinnost p\u0159em\u011bny energie sni\u017eovat, co\u017e vede k poklesu v\u00fdkonu nad ur\u010ditou frekvenc\u00ed.  Tento pokles je zp\u016fsoben ztr\u00e1tami energie v d\u016fsledku vnit\u0159n\u00edho t\u0159en\u00ed a dielektrick\u00fdch ztr\u00e1t v materi\u00e1lu.  Optimalizace geometrie desti\u010dky a volba vhodn\u00e9ho materi\u00e1lu s vysok\u00fdm piezoelektrick\u00fdm koeficientem a n\u00edzk\u00fdmi ztr\u00e1tami jsou kl\u00ed\u010dov\u00e9 pro dosa\u017een\u00ed vysok\u00e9 \u00fa\u010dinnosti v \u0161irok\u00e9m frekven\u010dn\u00edm rozsahu.<\/p>\n<p>Vliv teploty a st\u00e1rnut\u00ed<\/p>\n<p>Teplota a st\u00e1rnut\u00ed materi\u00e1lu mohou v\u00fdznamn\u011b ovlivnit frekven\u010dn\u00ed limit a celkovou funk\u010dnost piezoelektrick\u00e9 desti\u010dky.  Zm\u011bny teploty mohou zp\u016fsobit zm\u011bny mechanick\u00fdch a elektromechanick\u00fdch vlastnost\u00ed, co\u017e se projev\u00ed posunem rezonan\u010dn\u00ed frekvence.  St\u00e1rnut\u00ed materi\u00e1lu vede k degradaci jeho vlastnost\u00ed, v\u010detn\u011b sn\u00ed\u017een\u00ed piezoelektrick\u00e9ho koeficientu a zv\u00fd\u0161en\u00ed vnit\u0159n\u00edho t\u0159en\u00ed, co\u017e m\u016f\u017ee v\u00e9st ke sn\u00ed\u017een\u00ed \u00fa\u010dinnosti a posunu rezonan\u010dn\u00ed frekvence.  Pro dosa\u017een\u00ed dlouhodob\u00e9 stability je d\u016fle\u017eit\u00e9 zvolit materi\u00e1l s n\u00edzkou teplotn\u00ed z\u00e1vislost\u00ed a dobrou dlouhodobou stabilitou.<\/p>\n<p>Aplika\u010dn\u00ed aspekty a omezen\u00ed<\/p>\n<p>Frekven\u010dn\u00ed limit piezoelektrick\u00e9 desti\u010dky je d\u016fle\u017eit\u00fdm faktorem p\u0159i n\u00e1vrhu a aplikaci v r\u016fzn\u00fdch za\u0159\u00edzen\u00edch.  P\u0159i pou\u017eit\u00ed v ultrazvukov\u00fdch aplikac\u00edch, nap\u0159\u00edklad v senzorech nebo aktu\u00e1torech, je nutn\u00e9 zvolit desti\u010dku s dostate\u010dn\u011b vysokou rezonan\u010dn\u00ed frekvenc\u00ed pro dosa\u017een\u00ed po\u017eadovan\u00e9 frekvence ultrazvuku.  P\u0159ekro\u010den\u00ed frekven\u010dn\u00edho limitu m\u016f\u017ee v\u00e9st k neefektivn\u00edmu provozu, sn\u00ed\u017een\u00e9 \u00fa\u010dinnosti a potenci\u00e1ln\u00edmu po\u0161kozen\u00ed desti\u010dky.  Je proto nezbytn\u00e9 pe\u010dliv\u011b zv\u00e1\u017eit v\u0161echny relevantn\u00ed parametry, v\u010detn\u011b frekven\u010dn\u00edho limitu, p\u0159i v\u00fdb\u011bru a aplikaci piezoelektrick\u00fdch desek.<\/p>\n<p>Piezoelektrick\u00e9 desti\u010dky p\u0159edstavuj\u00ed d\u016fle\u017eit\u00fd prvek v mnoha technologi\u00edch.  Pochopen\u00ed jejich frekven\u010dn\u00edho limitu a souvisej\u00edc\u00edch vlastnost\u00ed je nezbytn\u00e9 pro optimalizaci jejich v\u00fdkonu a \u017eivotnosti v r\u016fzn\u00fdch aplikac\u00edch. Spr\u00e1vn\u00fd v\u00fdb\u011br materi\u00e1lu a geometrie je kl\u00ed\u010dov\u00fd pro dosa\u017een\u00ed po\u017eadovan\u00fdch parametr\u016f a spolehliv\u00e9ho provozu.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Piezoelektrick\u00e9 desti\u010dky nach\u00e1zej\u00ed \u0161irok\u00e9 uplatn\u011bn\u00ed v mnoha oblastech, od ultrazvukov\u00fdch senzor\u016f a aktu\u00e1tor\u016f po precizn\u00ed polohovac\u00ed syst\u00e9my. Kl\u00ed\u010dov\u00fdm parametrem ovliv\u0148uj\u00edc\u00edm jejich funk\u010dnost je v\u0161ak frekven\u010dn\u00ed limit, kter\u00fd ur\u010duje horn\u00ed hranici efektivn\u00edho provozu. Tento \u010dl\u00e1nek se podrobn\u011bji zam\u011b\u0159\u00ed na frekven\u010dn\u00ed limit piezoelektrick\u00fdch desek a n\u011bkter\u00e9 d\u016fle\u017eit\u00e9 vlastnosti, kter\u00e9 jej ovliv\u0148uj\u00ed. Mechanick\u00e9 vlastnosti a rezonan\u010dn\u00ed frekvence Frekven\u010dn\u00ed<\/p>\n","protected":false},"author":1,"featured_media":602,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6415],"tags":[],"class_list":["post-62636","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","prodpage-classic"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/62636","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/comments?post=62636"}],"version-history":[{"count":0,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/62636\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/media\/602"}],"wp:attachment":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/media?parent=62636"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/categories?post=62636"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/tags?post=62636"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}