Laser Phased Array Measurement of Simulated Solidified Weld Penetration Depth

1996 ◽  
Vol 118 (2) ◽  
pp. 266-271 ◽  
Author(s):  
J. Yang ◽  
T. Sanderson ◽  
G. Graham ◽  
C. Ume
Keyword(s):  
Penetration Depth ◽  
Weld Joint ◽  
Phased Array ◽  
Narrow Range ◽  
Weld Penetration ◽  
Maximum Resolution ◽  
Entire Thickness ◽  
Array Measurement ◽  
The Relationship ◽  
Array Receiver

This paper presents an experimental investigation of the use of an optical fiber laser phased array to measure solidified weld pool penetration depth in butt and v-groove joints. The purpose was to determine the optimum distances between the ultrasound source (the array), receiver, and the weld joint, in order to measure weld penetration depth. The relationship between penetration depth and wave amplitude was approximately linear. A narrow range of distances between the ultrasound receiver and weld joint permitted the ultrasonic system to detect penetration depth over the entire thickness of the base metal. Maximum resolution in measuring penetration depth was achieved by keeping the distance between the array and the weld joint as small as possible.

Real-Time Weld Penetration Depth Monitoring With Laser Ultrasonic Sensing System

2005 ◽  
Vol 128 (1) ◽  
pp. 280-286 ◽  
Author(s):  
Bao Mi ◽  
Charles Ume
Keyword(s):  
Real Time ◽  
Penetration Depth ◽  
Weld Pool ◽  
Phased Array ◽  
Welding Process ◽  
Analytical Relationship ◽  
Correlation Technique ◽  
Weld Penetration ◽  
Weld Quality ◽  
Sensing System

A real-time ultrasound-based system for controlling robotic weld quality by monitoring the weld pool is presented. The weld penetration depth is one of the most important geometric parameters that define weld quality, hence, remains a key control quantity. The sensing system is based on using a laser phased array technique to generate focused and steered ultrasound, and an electromagnetic acoustic transducer (EMAT) as a receiver. When a pulsed laser beam is incident on the surface of a condensed matter, either the thermoelastic expansion or ablation induces mechanical vibrations that propagate as ultrasound within the specimen. Both the ultrasound generation by the laser phased array and the reception by the EMAT are noncontact, which eliminates the need for a couplant medium. They are capable of operating at high temperatures involved in the welding process. The ultrasound generated by the laser phased array propagates through the weld pool and is picked up by the EMAT receiver. A signal-processing algorithm based on a cross-correlation technique has been developed to estimate the time-of-flight (TOF) of the ultrasound. The relationship between the TOF and the penetration depth of the weld has been established experimentally and analytically. The analytical relationship between the TOF and the penetration depth, which is obtained by the ray-tracing algorithm and geometric analysis, agrees well with the experimental measurements.

OCT-Einschweißtiefenüberwachung bei Unterdruck/OCT-based weld penetration monitoring at reduced ambient pressure – Influence of reduced ambient pressure on the OCT signal quality in laser deep penetration welding

2021 ◽  
Vol 111 (11-12) ◽  
pp. 863-868
Author(s):  
Thorsten Mattulat ◽  
Ronald Pordzik ◽  
Peer Woizeschke
Keyword(s):  
Penetration Depth ◽  
Ambient Pressure ◽  
Laser Beam Welding ◽  
In Situ Monitoring ◽  
Deep Penetration ◽  
Weld Penetration ◽  
Laser Deep Penetration Welding ◽  
Deep Penetration Welding ◽  
Non Destructive

Die optische Kohärenztomographie (OCT) erlaubt die zerstörungsfreie In-situ-Überwachung der Einschweißtiefe beim Laserstrahlschweißen. Für dieses Verfahren wird hier der Einfluss von verringerten Umgebungsdrücken auf die Messqualität untersucht. Es wird gezeigt, dass sich bei niedrigerem Umgebungsdruck deutlich größere Signalanteile aus dem Bereich des Bodens der Dampfkapillare zurückerhalten lassen. Auf diese Weise steigen die effektive Messfrequenz und die Erkennbarkeit von Änderungen der Einschweißtiefe.   Optical coherence tomography (OCT) enables non-destructive in-situ monitoring of the weld penetration depth during laser beam welding. For this technology, the influence of reduced ambient pressures on the measurement quality is investigated. It is shown that significantly larger signal components are obtained from the bottom of the vapor capillary at lower ambient pressure increasing the applicable measurement frequency and the detectability of changes in the weld penetration depth.

Experimental Investigation on Rotary Punching by the Compression of Polyurethane Pad

2014 ◽  
Vol 941-944 ◽  
pp. 1802-1807 ◽  
Author(s):  
Qian Liu ◽  
Jing Tao Han ◽  
Jing Liu ◽  
Xiao Xiong Wang
Keyword(s):  
Penetration Depth ◽  
Process Parameters ◽  
High Load ◽  
Large Area ◽  
Bear Capacity ◽  
Hole Edge ◽  
Quality Degradation ◽  
Series Of Experiments ◽  
Blanking Process ◽  
The Relationship

Rotary punching is a sheet metal blanking process which utilizes shearing tools fixed to a pair of rollers. The polyurethane pad is adopted as the die instead of rigid mold because it has the advantages of wide hardness range and high load-bear capacity. Due to the application of polyurethane pad, the surrounding region adjacent to the pierced hole will occur to plastically deform and deflect, which greatly differs from that in the conventional blanking. In this paper, the effects of blank material and thickness, polyurethane hardness, punch penetration depth on deformation behavior were mathematically analyzed and modeled, and then a series of experiments through varying process parameters were conducted to validate the relationship between process parameters and product quality. The degree of sample deflection was exactly measured by scanning electron microscope (SEM). The results show that the deformed area varies with different blank elongations and increases with increasing blank thickness for a given material. When polyurethane pad with low hardness level is employed, it results in large area deformation and quality degradation. Moreover, the deflection degree around the hole edge becomes more severe along with punch penetration, but the penetration depth along blank thickness is not in proportion to the amount of punch advancement.

scholarly journals Field validation of imaging an adjacent borehole using scattered P-waves

2020 ◽  
Vol 17 (5) ◽  
pp. 1272-1280
Author(s):  
Jian-Lin Ben ◽  
Wen-Xiao Qiao ◽  
Xiao-Hua Che ◽  
Xiao-Dong Ju ◽  
Jun-Qiang Lu ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Phased Array ◽  
Test Results ◽  
Field Validation ◽  
Geologic Structure ◽  
P Waves ◽  
Acoustic Reflection ◽  
Acoustic Receiver ◽  
Logging Tool ◽  
Array Receiver

Abstract Acoustic waves enter a rock formation from a borehole and are reflected or scattered upon encountering a geologic structure. Consequently, we obtain the structure location represented by the azimuth and distance from the borehole using the acoustic reflection or scattering. Downhole acoustic measurements with the azimuthal resolution are realized using an azimuthal acoustic receiver sonde composed of several arcuate phased array receivers. Eight sensors distributed evenly across the arcuate phased array receiver can record acoustic waves independently; this allows us to adopt the beamforming method. We use a supporting logging tool to conduct the downhole test in two adjacent fluid-filled boreholes, for validating the evaluation of the geologic structure using scattered P-waves. The test results show the multi-azimuth images of the target borehole and the azimuthal variation in scattering amplitudes. Thus, we obtain the precise location of the target borehole. Furthermore, the measured values of the target borehole are consistent with the actual values, indicating that we can accurately evaluate a near-borehole geologic structure with scattered P-waves.

Sign in / Sign up

Export Citation Format

Share Document