Robust mixed finite element simulations of interactions of ultrasonic waves with cracks

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989100%3A27240%2F16%3A86100169" target="_blank" >RIV/61989100:27240/16:86100169 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61989100:27740/16:86100169

Výsledek na webu

<a href="http://www.ndt.net/events/EWSHM2016/app/content/Paper/251_Lukas.pdf" target="_blank" >http://www.ndt.net/events/EWSHM2016/app/content/Paper/251_Lukas.pdf</a>

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Robust mixed finite element simulations of interactions of ultrasonic waves with cracks

Popis výsledku v původním jazyce

We are faced with interactions of ultrasonic waves with cracks in thin plates. These are important means in structural health monitoring of aircrafts. We present a couple of finite element models that are validated by means of Lamb dispersive (frequency-velocity) curves. In 2d it turns out that membranes and Kirchhoff plates imitate well the low frequency case of the lowest-order shear and bending modes, respectively. We switch to 3d displacement finite elements enhanced with higher-order ansatz functions in the thickness direction. These imitate properly the shear-horizontal modes, however, they suffer from the locking effect in case of the Lamb modes. We end up with 3d mixed elastic elements, which are referred to as tangential-displacements and normal-normal-stresses (TD-NNS), recently proposed and analyzed by Astrid Pechstein (born Sinwel) and Joachim Sch oberl at TU Vienna. We show that these new elements cover the whole spectrum of elastic waves including higher-order Lamb waves. Finally, relying on TD-NNS finite elements and a Newmark time discretization scheme we present simulations of interaction of ultrasonic waves with cracks.

Název v anglickém jazyce

Robust mixed finite element simulations of interactions of ultrasonic waves with cracks

Popis výsledku anglicky

We are faced with interactions of ultrasonic waves with cracks in thin plates. These are important means in structural health monitoring of aircrafts. We present a couple of finite element models that are validated by means of Lamb dispersive (frequency-velocity) curves. In 2d it turns out that membranes and Kirchhoff plates imitate well the low frequency case of the lowest-order shear and bending modes, respectively. We switch to 3d displacement finite elements enhanced with higher-order ansatz functions in the thickness direction. These imitate properly the shear-horizontal modes, however, they suffer from the locking effect in case of the Lamb modes. We end up with 3d mixed elastic elements, which are referred to as tangential-displacements and normal-normal-stresses (TD-NNS), recently proposed and analyzed by Astrid Pechstein (born Sinwel) and Joachim Sch oberl at TU Vienna. We show that these new elements cover the whole spectrum of elastic waves including higher-order Lamb waves. Finally, relying on TD-NNS finite elements and a Newmark time discretization scheme we present simulations of interaction of ultrasonic waves with cracks.

Druh

D - Stať ve sborníku

CEP obor

BA - Obecná matematika

OECD FORD obor

—

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

8th European Workshop on Structural Health Monitoring, EWSHM 2016

ISBN

978-1-5108-2793-6

ISSN

—

e-ISSN

—

Počet stran výsledku

8

Strana od-do

1154-1161

Název nakladatele

NDT.net

Místo vydání

Bad Breisig

Místo konání akce

Bilbao

Datum konání akce

5. 7. 2016

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

—