In Conventional ultrasonic non-destructive condition monitoring the testing personnel utilize his testing experience to interpret defects while analyzing the ultrasonic echo. Due to the coarse material structure, the ultrasonic wave attenuate more so sometimes it gives false impression of defect and provides unreliable results. The conventional inspection method is too subjective and highly relies on the effectiveness of testing personnel so the inspection reliability is low. To overcome these limitations a multi-interrogation ultrasonic technique and correlation of several parameters such as attenuation, acoustic velocity and grain size with material features is suggested in this paper.
1 Introduction
Non Destructive Testing (NDT) is the testing of materials, for surface or internal flaws or metallurgical condition, without rendering it unfit for service.
There are various NDT methods of inspecting the internal defects of complex surface parts, e.g. radiograph, eddy flow, ultrasonics, etc. Amongst these testing techniques, ultrasonic testing has an important role due to its strong penetration, good direction, high sensitivity, overall comparative low cost, and being harmless to the human body and the material of the parts.
Ultrasonic [1, 2, 3, 4] is a highly effective non destructive condition monitoring method which can detect even incipient faults. So Mean Time between Failure (MTBF) increases due to proactiveness and reduce Mean Time to Repair (MTTR) by improving trouble shooting capabilities. Ultrasonic nondestructive testing methods [5] play an important role in the physical characterization of engineering materials and in the assessment of their quality and serviceability in structures. In a wide range of different NDT me...
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When examining textile damages, two common techniques are considered i.e. macroscopically (with the naked eye) and microscopically examining the area that might have possible damages to the fabric. Also, looking at the characteristics of the area to discover whether the textile has been torn, punctured, cut etc...
Fatigue failure can be divided in three parts i.e. Crack initiation, Crack propagation and Final rupture.
The scattering particles in the skin consist of either lipids or proteins embedded in the fluids in and between skin cells. These fluids mainly consist of water. The lipid scatterers are found in the stratum corneum, in the cell membranes, and in the intracellular particles. The most efficient scatterers with respect to both scattering probability and scattering angle are those with dimensions close to the wavelength of the incoming light.Thus, cells themselves, with dimensions of the order of 10 µm, scatter ultraviolet radiation much less efficiently
Sound waves consist of a disturbance of air molecules, the vibrations which pass from molecule to molecules from the speaker to the ear of the listener. The rate at which particles in the medium vibrate in the disturbance is the frequency or pitch of the sound measured in hertz (cycles/sound). As the pitch increases there comes a frequency at about 20kHz when the sound is no longer audible and above the frequency disturbance, this is know as ultrasound. The first major breakthrough in the evolution of high frequency echo-sounding techniques came when the piezo-electric effect in certain crystals was discovered by Pierre and Jacques Curie in Paris in 1880. The turn of the century saw the invention of the Diode (component that restricts the direction of movement, allows an electric current to flow in one direction) and the Triode (type of vacu... ...
-Developed and implemented strip casting overseas to eliminate a step in the steel making process
Iqbal, M. K. (2013, March 27). NED University of Engineering and Technology. Retrieved from Department of Metallurgy Engineering: http://www.neduet.edu.pk/myd/TE/MY%20302.pdf
Grain size refers to a diameter of an individual particle and grain shape refers to the roundness or how close the shape is to a sphere. Navajo’s grain size averages at 0.2 millimeters in diameter and grain shape is well rounded and well sorted. Pottsville grain size averages at 3.81 centimeters in diameter and it is also well rounded, but it is not well sorted. Porosity is a measure (using meters) of how much empty space is in a rock and permeability is the measure (using Darcy) of ease in which liquid can move through a rock. Navajo’s porosity varies from 1.2% to 15% and the permeability ranges from 0.06md to 54md. Pottsville’s porosity varies from 11% to 15% and the permeability
Ultrasounds have been a part of the medical world since the 1940s. The affects of acoustic vibrations on the body were studied as early as the 6th century. Then, ultrasound gained widespread acceptance as a therapeutic trea...
A transducer is a mechanism that changes one form of energy to another form. A toaster is a transducer that turns electricity into heat; a loudspeaker is a transducer that changes electricity into sound. Likewise, an ultrasound transducer changes electricity voltage into ultrasound waves, and vice versa. This is possible because of the principle of piezoelectricity, which states that some materials (ceramics, quartz, and others) produce a voltage when deformed by an applied pressure. Conversely, piezoelectricity also results in production of a pressure whe...
This lab experiment was conducted in order to test the speed of sound, which is the distance traveled per unit time by a sound wave. This experiment was carried out with a certain setup, which involved materials such as a computer, a Logger Pro, a vernier microphone, two tubes, a temperature probe, a meter stick, and a dog trainer clicker. These materials were set up in a specific fashion, the Logger Pro was connected to the computer, which allowed for a temperature reading. The microphone was then connected to the lab interface and the two tubes were taped together from one end. One end of the tube was then placed against a wall, the microphone positioned near the open end of the tube as the dog clicker was pressed. Once the clicker was pressed, the speed of the sound traveling through the tube was collected by the microphone, the data then was inputted into the computer by the Logger Pro.
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These properties can be used for design and analysis of engineering structures, and for developing new materials that better suit a specified use. [8] Tensile tests are simple, relatively inexpensive, and fully standardised. By pulling on something, you will very quickly determine how the material will react to forces being applied in tension. As the material is being pulled, you will find its strength along with how much it will elongate and one of the more basic tests is to determine stress – strain relationships. [10] A simple uniaxial test consists of slowly pulling a sample of material in tension until it breaks. The major parameters that describe the stress-strain curve obtained during the tension test are the tensile strength (UTS), yield strength or yield point (σy), elastic modulus (E), percent elongation (∆L%) and the reduction in area (RA%). Toughness, Resilience, Poisson’s ratio (ν) can also be found by the use of this testing technique. 0.2 % off-set method is a commonly used method to determine the yield strength. Yield strength (σy) (0.2%) is found by drawing a parallel line to the elastic region and the point at which this line intersects with the stress-strain curve is set as the yielding point. [9] The following figure is the tensile tester that is used to test the
Medical ultrasound mechanisms produce ultrasound waves and accord the imitated echoes. Brightness mode (B mode) is the frank mode that is normally used.[2] The B mode gives a two dimensional (2D) black and white picture that depends on the anatomical locale of the slice. The body can be imaged in disparate planes reliant on the locale of the probe. These slender slices are of less than 1 mm every single and can be sagittal, coronal, transverse, or oblique. Sound waves are emitted from piezoelectric crystals from the ultrasound transducer. Piezoelectric crystals are fabricated from physical that adjustments mechanical signals to mechanical vibrations and adjustments mechanical vibrations to mechanical signals.[2] As ultrasound waves bypass across assorted body tissues, they are imitated back to the transducer crafting an picture on the ultrasound screen.[3] Aural impedance is described as the confrontation for propagation of ultrasound waves. This varies according to the density of the physical ultrasound passes through. After the physical is extra solid, nex...
Aircrafts undergo a variety of stresses, strains, vibrations, and detrimental environments. It is important to inspect the aircraft regularly in order to keep the aircraft operable, which inspections of the aircraft is a big part of proper maintenance. There are many types of inspection; the most common one is pre-flight inspection and post-flight inspection. Under the Canadian Aviation Regulations (CARs), a pre-flight inspection is mandatory for Pilot Proficiency Check. During a pre-flight inspection, the pilot should use the pre-flight checklist to perform an inspection on the exterior and interior of the aircraft. It is a chance for the pilot to check any defects on the aircraft that may cause a problem, and the readability of the radio signals.