Ultrasonic wave propagation in temperature gradients

Johnson, John A.; Carlson, Nancy M.; Lott, L. A.

doi:10.1007/bf00568010

Cited by 14 publications

(2 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8,13 2-D ray tracing has been studied and applied to ultrasonic wave propagation in temperature gradients based on Snell's law. 14 In this paper, a 3-D ray tracing algorithm based on Fermat's principle is presented. First of all, the temperature field within the weld sample is obtained by FEA.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional ray tracing of laser ultrasound for weld penetration sensing

Ume

2004

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

The time-of-flight ͑TOF͒ method is an ultrasonic nondestructive testing ͑NDT͒ technique. The TOF of an ultrasonic wave can be correlated to weld penetration depth, and hence weld quality. Changes in material properties due to temperature gradients will cause ultrasonic speed to vary during welding, which causes a curved propagation path. A ray tracing algorithm is required in order to study how ultrasound propagates within a weld sample. In this paper, a three-dimensional ͑3-D͒ ray tracing algorithm based on Fermat's principle is presented. First, ray equations are derived using the calculus of variation. Then, a numerical algorithm is developed to solve the derived ray equations and obtain the curved propagation path. This algorithm includes finite element analysis ͑FEA͒ to obtain the transient temperature distribution during the welding and shooting method to solve the boundary value problem. After the curved ray path is obtained, the TOF can be found by integrating the time variable along the ray path. An analytical relationship between the TOF and penetration depth can be established by repeating the ray tracing algorithm for different penetration depths. Experimental measurements of TOF have been performed, and this data is to be used to validate the numerical results.

show abstract

Section: Introductionmentioning

confidence: 99%

Three-dimensional ray tracing of laser ultrasound for weld penetration sensing

Ume

2004

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

show abstract

“…Among the methods proposed in the existing literature, pool oscillation [1][2][3] and infrared sensing [4][5][6] based methods received most attention. Ultrasonic sensing [7][8][9] has also been used, but it requires additional sensing devices which are difficult to attach to the torch. Acoustic emission sensing [10] can distinguish between full penetration and partial penetration.…”

Section: Introductionmentioning

confidence: 99%

Weld pool surface depth measurement using a calibrated camera and structured light

Saeed

Zhang

2007

Meas. Sci. Technol.

View full text Add to dashboard Cite

Automated monitoring and control of the weld pool surface has been one of the goals of the welding industry. This paper presents a technique which uses a calibrated charge-coupled device (CCD) sensor and structured light to extract the surface information as depth of pool from captured images. It projects a laser line from a predetermined position onto the specular weld pool surface. A reflected laser beam from the specular surface is captured by a calibrated CCD sensor to form the image. The image is then processed based on the ray-tracing technique to calculate the depth of the weld pool surface using the position of the laser and its fan angle along with the intrinsic parameters and extrinsic parameters of the CCD sensor.

show abstract

Theoretical assessment of the errors involved in ultrasonic location and sizing of molten weld pools

Ogilvy

Temple

1990

Ultrasonics

View full text Add to dashboard Cite

Ultrasonic wave propagation in temperature gradients

Cited by 14 publications

References 2 publications

Three-dimensional ray tracing of laser ultrasound for weld penetration sensing

Three-dimensional ray tracing of laser ultrasound for weld penetration sensing

Weld pool surface depth measurement using a calibrated camera and structured light

Theoretical assessment of the errors involved in ultrasonic location and sizing of molten weld pools

Contact Info

Product

Resources

About