Detection of Internal Holes in Additive Manufactured Ti-6Al-4V Part Using Laser Ultrasonic Testing

For a non-contact, non-destructive quality evaluation, laser ultrasonic testing (LUT) has received increasing attention in complex manufacturing processes, such as additive manufacturing (AM). This work assessed the LUT method for the inspection of internal hole defects in additive manufactured Ti-6Al-4V part. A Q-switched pulsed laser was utilized to generate ultrasound waves on the top surface of a Ti-6Al-4V alloy part, and a laser Doppler vibrometer (LDV) was utilized to detect the ultrasound waves. Sub-millimeter (0.8 mm diameter) internal hole defect was successfully detected by using the established LUT system in pulse-echo mode. The method achieved a relatively high resolution, suggesting significant application prospects in the non-destructive evaluation of AM part. The relationship between the diameter of the hole defects and the amplitude of the laser-generated Rayleigh waves was studied. X-ray computed tomography (XCT) was conducted to validate the results obtained from the LUT system.

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Parametric optimization of pulse-echo laser ultrasonic system for inspection of thick polymer matrix composites

Structural Health Monitoring ◽

10.1177/1475921719852891 ◽

2020 ◽

Vol 19 (2) ◽

pp. 443-453 ◽

Cited By ~ 1

Author(s):

AD Abetew ◽

TC Truong ◽

SC Hong ◽

JR Lee ◽

JB Ihn

Keyword(s):

Composite Structures ◽

Polymer Matrix Composites ◽

Matrix Composites ◽

Non Destructive Testing ◽

Destructive Testing ◽

Laser Ultrasonic ◽

Ultrasonic Signals ◽

Peak Energy ◽

Pulse Echo ◽

Non Destructive

One of the main challenges of using laser ultrasonic techniques for non-destructive testing applications is the typically low signal-to-noise ratio of the laser ultrasonic signals. In the case of thick composite structures, this is even more problematic since composite materials have very strong sound attenuation. This article investigates the effects of laser beam size and profile to the amplitude of pulse-echo laser ultrasonic signals with the constraint that the peak energy density (fluence) must be kept constant under the thermal damage threshold of material like polymer matrix composites. Such constraint is very important for the non-destructive feature of non-destructive testing, yet in a number of the existing parameter studies of laser ultrasonics, it was not fully investigated. In this article, a series of A-scan and C-scan experiments on thick composite specimens shows that the amplitude of the direct waves and the reflected waves increases with the increase in laser beam size with constant peak energy density. This amplitude enhancement significantly improves the propagation depth, thereby optimizing the system for inspection of thick composite structures. The validity of experimental results is verified theoretically by solving the thermoelastic model of epicenter displacement using Laplace–Hankel transformation.

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Laser-Ultrasonic Testing of the Structure and Properties of Concrete and Carbon Fiber-Reinforced Plastics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.722.267 ◽

2016 ◽

Vol 722 ◽

pp. 267-272 ◽

Cited By ~ 12

Author(s):

Alexander N. Kravcov ◽

Pavel Svoboda ◽

Adam Konvalinka ◽

Elena B. Cherepetskaya ◽

Alexsander A. Karabutov ◽

...

Keyword(s):

Ultrasonic Testing ◽

Structure And Properties ◽

Laser Ultrasonic ◽

Testing Technique ◽

Carbon Fiber Reinforced Plastics ◽

Reinforced Plastics ◽

Wave Velocities ◽

Fiber Reinforced Plastics ◽

Non Destructive ◽

2D Images

This paper discusses the possibility of studying composite materials by non-destructive laser-ultrasonic testing technique. Concrete samples and carbon-epoxy composites were examined, defects located and elastic wave velocities measured. The internal structure of the samples was visualized in 2D images.

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Artifact reduction in non-destructive testing by means of complementary data fusion of x-ray computed tomography and ultrasonic pulse-echo testing

Measurement Science and Technology ◽

10.1088/0957-0233/24/12/125403 ◽

2013 ◽

Vol 24 (12) ◽

pp. 125403 ◽

Cited By ~ 9

Author(s):

Michael Schrapp ◽

Thomas Scharrer ◽

Matthias Goldammer ◽

Stefan J Rupitsch ◽

Alexander Sutor ◽

...

Keyword(s):

Computed Tomography ◽

Data Fusion ◽

Ultrasonic Pulse ◽

Artifact Reduction ◽

Non Destructive Testing ◽

Destructive Testing ◽

X Ray ◽

X Ray Computed ◽

Pulse Echo ◽

Non Destructive

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Applying Ultrasonic Testing to Detect Hole Defect Near the Surface

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.194-196.2054 ◽

2011 ◽

Vol 194-196 ◽

pp. 2054-2057 ◽

Cited By ~ 1

Author(s):

Ming Kuen Chang ◽

Hua Sui Sun ◽

Jyun Cang Ciou

Keyword(s):

Ultrasonic Testing ◽

Delay Line ◽

Medium Carbon Steel ◽

Structural Safety ◽

Near Surface ◽

Straight Beam ◽

Hole Defect ◽

Wire Cutting ◽

The Relationship ◽

Flaw Shape

During materials manufacturing process will cause defects occasionally, if the defects located at near surface of material where the testing is not easy to implement. When the defects was stress by outside loading, it will grow up even become fracture, if the material apply ultrasonic testing then can increase material security to ensure structural safety. Practice material defect shape is variable and need complex product procedure. In this study, using wire cutting method to make practice defects specimen instead of the real flaws material, the specimen was made of medium carbon steel and aluminum alloy, defects away from the surface is 2-4 mm, defect shape including round shape hole and square shape hole, bore diameter was 1-3 mm. Using ultrasonic straight beam probe and delay line probe, straight beam probe have 5 MHz and 10 MHz frequency, and delay line probe have 5 MHz, 10 MHz frequency too, finally, compared the relationship between the accuracy and depth of flaws, pore size, flaw shape, material of specimen. Research results demonstrate that accuracy didn’t relate to the flaw shape, flaw size, depth of flaws and material of specimen. The accurately of 10 MHz delayed probe shown the depth of flaw smaller, the measurement than other probes.

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Effect of autogenous crack self-healing on mechanical strength recovery of cement mortar under various environmental exposure

Scientific Reports ◽

10.1038/s41598-021-86596-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

A. R. Suleiman ◽

M. L. Nehdi

Keyword(s):

Mechanical Strength ◽

Self Healing ◽

Surface Cracks ◽

Ongoing Debate ◽

Multi Scale ◽

Strength Recovery ◽

Broad Array ◽

X Ray Computed ◽

The Relationship ◽

Non Destructive

AbstractWhile research on self-healing of cement-based materials has recently gained considerable attention and made sizable progress, there is still ongoing debate and controversy regarding the effect of crack closing induced by autogenous self-healing on mechanical strength recovery. Despite that several techniques have been used to capture and quantify the self-healing of surface cracks, the resulting effect on mechanical strength has not, to date, been explored and quantified in a rigorous and systematic manner. Therefore, in this study, a broad array of multi-scale techniques including non-destructive shear wave velocity, high-resolution X-ray computed tomography (µCT), and 3D image analysis was deployed to examine the effects of autogenous crack self-healing on the mechanical strength recovery in various mortar specimens. The influence of microstructural changes induced by additives such as swelling compounds, silica-based additions, and carbonating minerals on strength recovery under diverse environmental exposures was further explored. The results capture the relationship between the crack closing mechanism imparted by self-healing and mechanical strength recovery, therefore elucidating the discrepancies in mechanical strength recovery results reported in the open literature.

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