Finite element simulation of temperature field of thin tubes irradiated by ring lasers

CAO Dou-dou; WANG Kai-sheng; YANG Yan-nan

doi:10.3969/j.issn.1001-3806.2010.06.010

In order to improve the efficiency of ultrasound excited by pulsed laser in a thin tube,a laser-ultrasonic model of an aluminum tube irradiated by a ring laser was established based on thermo-elastic theory of laser-ultrasound.The transient temperature field of the interior surface of the aluminum tube irradiated by a pulse ring laser was simulated by means of finite element method.Then the evolution curves of the temperature with time,radial and axial variables were obtained.Furthermore, the formation and variation of temperature gradient in the interior of aluminum tubes was analyzed.Results show that transient temperature field can be set up in a few tens of nanoseconds under the irradiation of a pulsed ring laser.Enormous temperature gradient produces in this process and a very strong ultrasonic wave appears subsequently in the aluminum tube.Because temperature gradient distributes on the entire circle,the ultrasonic wave spreading in tube attenuates slowly,which is useful for ultrasonic detection on large region along circle and axis of the tube.The results may provide valuable reference for the laser-generated thermo-elastic ultrasonic guided wave pipeline.

Finite element simulation of temperature field of thin tubes irradiated by ring lasers

Corresponding author: YANG Yan-nan, yanhyn@nuaa.edu.cn

1. Department of Applied Physics, Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China

Received Date: 2009-11-20

Accepted Date: 2010-02-23

Available Online: 2010-11-25

Abstract: In order to improve the efficiency of ultrasound excited by pulsed laser in a thin tube,a laser-ultrasonic model of an aluminum tube irradiated by a ring laser was established based on thermo-elastic theory of laser-ultrasound.The transient temperature field of the interior surface of the aluminum tube irradiated by a pulse ring laser was simulated by means of finite element method.Then the evolution curves of the temperature with time,radial and axial variables were obtained.Furthermore, the formation and variation of temperature gradient in the interior of aluminum tubes was analyzed.Results show that transient temperature field can be set up in a few tens of nanoseconds under the irradiation of a pulsed ring laser.Enormous temperature gradient produces in this process and a very strong ultrasonic wave appears subsequently in the aluminum tube.Because temperature gradient distributes on the entire circle,the ultrasonic wave spreading in tube attenuates slowly,which is useful for ultrasonic detection on large region along circle and axis of the tube.The results may provide valuable reference for the laser-generated thermo-elastic ultrasonic guided wave pipeline.

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Reference (14)

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Finite element simulation of temperature field of thin tubes irradiated by ring lasers

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