scholarly journals Characterizing Depth of Defects with Low Size/Depth Aspect Ratio and Low Thermal Reflection by Using Pulsed IR Thermography

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1886
Author(s):  
Alexey I. Moskovchenko ◽  
Michal Švantner ◽  
Vladimir P. Vavilov ◽  
Arsenii O. Chulkov
Keyword(s):  
Quantitative Estimation ◽  
Signal Reconstruction ◽  
Heat Diffusion ◽  
Defect Characterization ◽  
Ir Thermography ◽  
Defect Depth ◽  
Depth Prediction ◽  
Aspect Ratios ◽  
3D Printed ◽  
Novel Method

This study is focused on the quantitative estimation of defect depth by applying pulsed thermal nondestructive testing. The majority of known defect characterization techniques are based on 1D heat conduction solutions, thus being inappropriate for evaluating defects with low aspect ratios. A novel method for estimating defect depth is proposed by taking into account the phenomenon of 3D heat diffusion, finite lateral size of defects and the thermal reflection coefficient at the boundary between a host material and defects. The method is based on the combination of a known analytical model and a non-linear fitting (NLF) procedure. The algorithm was verified both numerically and experimentally on 3D-printed polylactic acid plastic samples. The accuracy of depth prediction using the proposed method was compared with the reference characterization technique based on thermographic signal reconstruction to demonstrate the efficiency of the proposed NLF method.

scholarly journals Additively Manufactured Parts Made of a Polymer Material Used for the Experimental Verification of a Component of a High-Speed Machine with an Optimised Geometry—Preliminary Research

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 137
Author(s):  
Artur Andrearczyk ◽  
Bartlomiej Konieczny ◽  
Jerzy Sokołowski
Keyword(s):  
Polymer Material ◽  
High Speed ◽  
Numerical Models ◽  
Flow Analysis ◽  
Experimental Tests ◽  
Strength Analysis ◽  
Compressor Wheel ◽  
Operational Characteristics ◽  
3D Printed ◽  
Novel Method

This paper describes a novel method for the experimental validation of numerically optimised turbomachinery components. In the field of additive manufacturing, numerical models still need to be improved, especially with the experimental data. The paper presents the operational characteristics of a compressor wheel, measured during experimental research. The validation process included conducting a computational flow analysis and experimental tests of two compressor wheels: The aluminium wheel and the 3D printed wheel (made of a polymer material). The chosen manufacturing technology and the results obtained made it possible to determine the speed range in which the operation of the tested machine is stable. In addition, dynamic destructive tests were performed on the polymer disc and their results were compared with the results of the strength analysis. The tests were carried out at high rotational speeds (up to 120,000 rpm). The results of the research described above have proven the utility of this technology in the research and development of high-speed turbomachines operating at speeds up to 90,000 rpm. The research results obtained show that the technology used is suitable for multi-variant optimization of the tested machine part. This work has also contributed to the further development of numerical models.

A Novel Method for Constructing Multi-Mode Deployable Polyhedron Mechanisms Using Symmetric Spatial RRR Compositional Units

2018 ◽  
Author(s):  
Jieyu Wang ◽  
Xianwen Kong
Keyword(s):  
Kinematic Chain ◽  
Degree Of Freedom ◽  
Single Loop ◽  
Kinematic Chains ◽  
The Third ◽  
Motion Modes ◽  
3D Printed ◽  
Novel Method ◽  
Multi Mode ◽  
Motion Mode

A novel construction method is proposed to construct multimode deployable polyhedron mechanisms (DPMs) using symmetric spatial RRR compositional units, a serial kinematic chain in which the axes of the first and the third revolute (R) joints are perpendicular to the axis of the second R joint. Single-loop deployable linkages are first constructed using RRR units and are further assembled into polyhedron mechanisms by connecting single-loop kinematic chains using RRR units. The proposed mechanisms are over-constrained and can be deployed through two approaches. The prism mechanism constructed using two Bricard linkages and six RRR limbs has one degree-of-freedom (DOF). When removing three of the RRR limbs, the mechanism obtains one additional 1-DOF motion mode. The DPMs based on 8R and 10R linkages also have multiple modes, and several mechanisms are variable-DOF mechanisms. The DPMs can switch among different motion modes through transition positions. Prototypes are 3D-printed to verify the feasibility of the mechanisms.

scholarly journals Experimental and Numerical Study on Characterization and Evaluation of Surface Cracks with Wireless Ultrasonic Sensor

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Shuo Chen ◽  
Jing Li ◽  
Donghui Huang ◽  
Yuzhi Chen ◽  
Haitao Zhao
Keyword(s):  
Numerical Study ◽  
Experimental Testing ◽  
Quantitative Estimation ◽  
Signal Reconstruction ◽  
Characteristic Parameter ◽  
Crack Size ◽  
Waveform Analysis ◽  
Fe Model ◽  
Surface Cracks ◽  
Artificial Surface

Adopting both wireless ultrasonic sensing and numerical simulation techniques, this research investigates the interaction between Rayleigh wave and artificial surface cracks of varying depths. When analyzing experimental ultrasonic data collected by a wireless sensing node, the signals are enhanced through a two-step procedure including signal reconstruction and envelope extraction. The waveforms are interpreted in detail by analyzing wave components through time-of-flight technique. A finite element (FE) model is devised to properly simulate the experimental testing. The simulated waveforms are consistent with experimental results and corroborate the analysis and explanations of experimental waveforms. Based on both experimental and numerical waveform analysis, a relationship between ultrasonic characteristic parameter and crack size is established for the quantitative estimation purpose. The proposed model shows a good agreement with data from both test and literatures.

Specified value based defect depth prediction using pulsed thermography

2012 ◽  
Vol 112 (2) ◽  
pp. 023112 ◽  
Author(s):  
Zhi Zeng ◽  
Ning Tao ◽  
Lichun Feng ◽  
Cunlin Zhang
Keyword(s):  
Defect Depth ◽  
Pulsed Thermography ◽  
Depth Prediction

scholarly journals Dynamics and length scales in vertical convection of liquid metals

2021 ◽  
Vol 932 ◽  
Author(s):  
Lukas Zwirner ◽  
Mohammad S. Emran ◽  
Felix Schindler ◽  
Sanjay Singh ◽  
Sven Eckert ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Liquid Metals ◽  
Global Response ◽  
Response Characteristics ◽  
Aspect Ratios ◽  
Time Space ◽  
Shaped Container ◽  
Novel Method ◽  
Space Data ◽  
Rayleigh Numbers

Using complementary experiments and direct numerical simulations, we study turbulent thermal convection of a liquid metal (Prandtl number $\textit {Pr}\approx 0.03$ ) in a box-shaped container, where two opposite square sidewalls are heated/cooled. The global response characteristics like the Nusselt number ${\textit {Nu}}$ and the Reynolds number $\textit {Re}$ collapse if the side height $L$ is used as the length scale rather than the distance $H$ between heated and cooled vertical plates. These results are obtained for various Rayleigh numbers $5\times 10^3\leq {\textit {Ra}}_H\leq 10^8$ (based on $H$ ) and the aspect ratios $L/H=1, 2, 3$ and $5$ . Furthermore, we present a novel method to extract the wind-based Reynolds number, which works particularly well with the experimental Doppler-velocimetry measurements along vertical lines, regardless of their horizontal positions. The extraction method is based on the two-dimensional autocorrelation of the time–space data of the vertical velocity.

scholarly journals DEVELOPMENT AND VALIDATION OF UV SPECTROPHOTOMETRICMETHOD FOR QUANTITATIVE ESTIMATION OF GLIPIZIDEIN PHARMACEUTICAL DOSAGE FORM

2020 ◽  
pp. 104-107
Author(s):  
ANUJA SURYAWANSHI ◽  
AFAQUEANSARI ◽  
MALLINATH KALSHETTI
Keyword(s):  
Dosage Form ◽  
Limit Of Detection ◽  
Quantitative Estimation ◽  
The Novel ◽  
Limit Of Quantification ◽  
Pharmaceutical Dosage Form ◽  
Novel Method ◽  
Bulk Drug ◽  
Development And Validation

Objective: The present work is aimed to develop a simple, rapid, selective and economical UV spectrophotometric method for quantitative determination of Glipizideinbulk and pharmaceutical dosage form. Methods: In this method Dimethyl Form amide (DMF) was used as solvent, the absorption maxima was found to be275 nm in DMF. The developed method was validated for linearity, accuracy, precision, ruggedness, robustness, LOD and LOQ in accordance with the requirements of ICH guideline. Results: The linearity was found to be 10-60 µg/ml having linear equation y=0.017x-0.006 with correlation coefficient of 0.997. The% recovery was found to be in the range of 98.7-100%. The % RSD for intra-day and inter-day precision was found to be 0.569923 and 0.40169 respectively. The limit of detection (LOD) and limit of quantification (LOQ) was found to be3.06 µg/ml and 9.27 µg/ml respectively. Conclusion: The developed method was validated as per ICH Q2(R1) guidelines. The novel method is applicable for the analysis of bulk drug in its pharmaceutical dosage form.

Evaluation of Paravalvular Leakage in Novel Mechanical Heart Valve

2017 ◽  
Author(s):  
Ankit Saxena ◽  
Rohan Shad ◽  
Mrudang Mathur ◽  
Anwesha Chattoraj ◽  
Sujay Shad
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Cardiac Tissue ◽  
Mechanical Heart Valve ◽  
Prosthetic Heart Valve ◽  
3D Printed ◽  
Novel Method ◽  
Novel Devices ◽  
Careful Assessment ◽  
Unique Mechanism

We developed a new mechanical heart valve prototype with a unique mechanism for attachment to cardiac tissue. The development of novel prosthetic heart valve systems requires careful assessment of paravalvular leaks — leakage of fluid that takes place between the valve and the cardiac tissue it is attached to. Traditional methods of testing paravalvular leaks in flow chambers are not ideal for novel devices and may underestimate its true extent. In this paper we developed a novel method of quantifying paravalvular leaks involving the use of 3D printed prototype heart valves and cadaveric bovine hearts, and compared the results with those from commercially available Medtronic ATS mechanical bileaflet valves. The average leak in our final prototype heart valves were found to be 0.13 ml/sec, compared to 0.33 ml/sec in the ATS valve.

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