DISBOND DETECTION TECHNIQUE FOR LINER/PROPELLANT INTERFACE USING ULTRASONIC RESONANCE AND LAMB WAVES

2012 ◽  
Vol 06 ◽  
pp. 49-54
Author(s):  
DONG-RYUN KIM ◽  
JAE-HOON KIM
Keyword(s):  
Lamb Waves ◽  
Resonance Method ◽  
Multilayered Structure ◽  
Ultrasonic Waves ◽  
Multilayered Structures ◽  
Reflected Waves ◽  
Nondestructive Tests ◽  
Ultrasonic Resonance ◽  
A New Technique ◽  
Insulation Liner

Adhesive interface tests using ultrasonic waves are far superior to other nondestructive tests for detecting the disbond interface. However, a multilayered structure consisting of a steel case, rubber insulation, liner, and propellant poses many difficulties for analyzing ultrasonic waves because of the superposition of the reflected waves and the large differences in the acoustic impedances of the various materials. Therefore, ultrasonic tests for detecting the disbond interface of multilayered structures have been applied in very limited areas between the steel case and rubber insulation using an automatic system. The existing ultrasonic test cannot detect the disbond interface between the rubber and propellant of a multilayered structure because most of the ultrasonic waves are absorbed in the rubber material, which has low acoustic impedance. This problem could be overcome by amplifying the ultrasonic waves using the ultrasonic resonance method. The Lamb waves were used to evaluate the instability of the ultrasonic waves caused by the contact condition on the surface of the multilayered structure. In this paper, a new technique to detect the disbond interface between the liner and propellant using the property of ultrasonic resonance and Lamb waves is discussed in detail.

scholarly journals Defect Detection of Aluminium Plates Based on Near-Field Enhancement of Lamb Waves Generated Using an Electromagnetic Acoustic Tranducer

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3529 ◽  
Author(s):  
Zhou ◽  
Zhang ◽  
Xu ◽  
Ren
Keyword(s):  
Lamb Waves ◽  
Near Field ◽  
Broadband Ultrasound Attenuation ◽  
Field Enhancement ◽  
Ultrasonic Waves ◽  
Traditional Methods ◽  
Electromagnetic Acoustic Transducers ◽  
Acoustic Transducers ◽  
Important Means ◽  
Pulse Echo

Ultrasonic testing is an important means to detect defacing defects, such as scratches and cracks, but when the size of these defects is smaller than the wavelength of ultrasonic waves, it is difficult to detect them using traditional methods like the pulse-echo method and broadband ultrasound attenuation method for the diffraction of ultrasonic waves at the defects. Based on the non-contact characteristic of electromagnetic acoustic transducers (EMATs), a transducer for scanning inspection was developed in this paper. The transducer was utilized to detect and measure the depth of the defacing defects on an aluminium plate based on the near-field enhancement of ultrasonic Lamb waves. The results show that the amplitude of the S0 Lamb wave experiences a large enhancement when the transducer is passed over the scratch defects and the enhancement has a clearly positive correlation with the depth of the scratch defects. When the depth increases from 0.1 mm to 0.9 mm, the amplitude of S0 Lamb waves increases from 1.13 times to 2.27 times the S0 Lamb waves received on the aluminium plate without defects. The new method can be utilized to detect the defacing defects on the aluminium plate and get better detection effects than the traditional methods without analyzing the relatively small reflection waves.

Dynamic Stress Analysis of Multilayered Structure With Radial Gaps of Cylindrical Pressure Vessel Under Plane Strain Conditions

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Huadong Liu ◽  
Weiqiang Wang
Keyword(s):  
Plastic Deformation ◽  
Dynamic Response ◽  
Plane Strain ◽  
Pressure Vessel ◽  
Single Layer ◽  
Multilayered Structure ◽  
Multilayered Structures ◽  
Loading Process ◽  
Cylindrical Pressure Vessel ◽  
Gap Height

Radial gaps were found in multilayered cylindrical vessels which experience inner explosion accidents in chemical plants in the past few years worldwide. It is necessary to investigate the dynamic response of multilayered structures with radial gaps to ensure the vessel safety. This paper presented a numerical modeling of the dynamic response of a multilayered structure with radial gaps of cylindrical pressure vessel under plane strain conditions by using the ANSYS/ls-dyna package. The effects of the dynamic loading profile and the radial gap height are considered in the investigation. The stress spatial distribution, the stress and the plastic deformation variation curves with time are emphatically analyzed. The results show that the stress variation of the entire loading process can be divided into four stages: the oscillation stage, the yield stage, the fast increase stage, and the redistribution stage. The layer stress distributes discontinuously at the gaps between layers and distributes unevenly in any single layer. The inner layer stress is not always larger than the outer layers' during the whole loading process. The effect of loading profile on the dynamic response is not as obvious as the gap height. As the gap height increases, the stress oscillation stage is suppressed and becomes shorter. While the loading recovers to the operation pressure, the stress and the plastic deformation of inner layers increases and vice versa for the outer layers.

Structural Health Monitoring of Thin Aluminum Plate Using Acoustic Sensors

2012 ◽  
Vol 622-623 ◽  
pp. 1389-1395
Author(s):  
R. Nishanth ◽  
K. Lingadurai ◽  
V. Malolan ◽  
Gowrishankar Wuriti ◽  
M.R.M. Babu
Keyword(s):  
Lamb Wave ◽  
Damage Identification ◽  
Lamb Waves ◽  
Time Domain Analysis ◽  
Ultrasonic Waves ◽  
Aluminum Plate ◽  
Identification System ◽  
Time Frequency ◽  
Thin Aluminum ◽  
Aluminum Plates

SHM is defined as “an emerging technology that can be defined as continuous, autonomous, real time, in-service monitoring of the physical condition of a structure by means of embedded or attached sensors with minimum manual intervention” .SHM provides the ability of a system to detect adverse changes within a system’s structure to enhance reliability and reduce maintenance costs. There are different Non-Destructive techniques like acoustic emission, ultrasonic, acousto-ultrasonic, guided ultrasonic waves or Lamb waves which are nowadays investigated for the development of an efficient and user-friendly damage identification system. This paper deals with the latter which is based on Lamb wave propagation. It has been developed especially for distinguishing different kinds of damages. The Lamb wave-based active SHM method uses piezoelectric (PZT) sensors to transmit and receive Lamb waves in a thin Aluminum plate. The Lamb wave modes (AO &SO) travel into the structure and are reflected by the structural boundaries, discontinuities, and damage. By studying their propagation and reflection, the presence of defect in the structure is determined. Laboratory level experiments have been carried out on thin Aluminum plates with angular, horizontal and vertical defect. The obtained waveform is filtered to avoid unwanted noise & disturbances using Savitzky-Golay filtering. The filtered waveforms are compared to differentiate the defects. Short Time Fourier Transform has been carried out on the acquired waveform. This study provides significant insight into the problem of identifying localized damages in the structure using PZT and dispersion of signal after they interact with different types of damage. Those small defects like the horizontal one that may be nearly missed in time domain analysis can also be clearly identified in the STFT analysis. Moreover the occurrence of So mode is also clearly seen. Thus, Lamb waves generated by PZT sensors and time-frequency analysis techniques could be used effectively for damage detection in aluminum plate. This study has given a complete idea of the working and the basic requirements of SHM system.

Ultrasonic Investigations of Inclusion Complexation of α-Cyclodextrin by DMSO in Pseudo-Binary Aqueous System

2015 ◽  
Vol 40 (4) ◽  
pp. 569-574
Author(s):  
Milena Kaczmarek-Klinowska ◽  
Tomasz Hornowski ◽  
Andrzej Skumiel ◽  
Monika Jażdżewska
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Heat Capacity ◽  
Inclusion Complexation ◽  
Adiabatic Compressibility ◽  
Resonance Method ◽  
Molecular Complexes ◽  
Aqueous System ◽  
Ultrasonic Waves ◽  
Stoichiometric Ratio

Abstract The paper reports the study of the complexation processes in aqueous solution of α-CD and DMSO. Cyclodextrins (CDs) (sometimes called cycloamyloses) are cyclic oligosaccharides formed by glucose units interconnected by α-(1,4) linkages; α-CD is one of three the most common CDs. It consists of six glucopyranose units. The speed of ultrasonic waves has been measured by the resonance method on ResoscanTM System apparatus. Some collateral data, such as density and heat capacity of the system, have also been measured. On the basis of the experimental data the excess adiabatic compressibility was determined. The extremes of the excess adiabatic compressibility function for different mixture compositions allowed us to establish the composition of molecular complexes formed in the solution. The obtained results suggest the formation of the α-CD with DMSO inclusion complexes with chemical stoichiometric ratio value of 1:1.

Monitoring of Stamping Process Using Ultrasonic Waves

2016 ◽  
Author(s):  
S. Mishra ◽  
P. K. Kankar ◽  
M. Ishihama
Keyword(s):  
Automobile Industry ◽  
Ultrasonic Waves ◽  
Work Piece ◽  
Full Potential ◽  
Workpiece Material ◽  
Reflected Waves ◽  
Stamping Process ◽  
Transmitted Waves ◽  
The Press ◽  
The Waves

Stamping is a core manufacturing process in automobile industry. The measurement of the press force in stamping process has been the major focus of the research in this area. However, it has been established that the press force is itself an integral of the pressure distribution over the contact surfaces. Also full potential of servo-control stamping machines has not yet been achieved due to lack of appropriate sensing functions. In this study, an effort has been made to monitor the stamping process with the help of ultrasonic waves. The waves are employed to obtain the contact conditions between the work piece and the die. It has been shown that the waveforms are affected not only by the workpiece material and its thickness but also by the angle of inclination. Results show that the reflected waves, being more sensitive than transmitted waves, are influenced by the change in work piece related parameters.

Condition monitoring of mechanical seals: Detection of film collapse using reflected ultrasonic waves

2000 ◽  
Vol 214 (9) ◽  
pp. 1187-1194 ◽  
Author(s):  
D Anderson ◽  
J Jarzynski ◽  
R. F. Salant
Keyword(s):  
Steady State ◽  
Piezoelectric Transducer ◽  
Ultrasonic Waves ◽  
Mechanical Seal ◽  
Mechanical Seals ◽  
Reflected Waves ◽  
Bench Tests ◽  
State Tests ◽  
Lubricating Film ◽  
Film Collapse

A method for detecting the collapse of the lubricating film in a mechanical seal has been developed. A piezoelectric transducer is placed behind the non-rotating seal face and is used to generate ultrasonic waves, which propagate towards the interface between the two seal faces. The same transducer is used to detect the reflected waves, whose amplitude is a measure of the degree of contact between the faces. The results of bench tests, steady-state tests and transient tests show that the method is effective.

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