Integration of periodic structure and highly narrowband MEMS sensor to enhance crack detection ability in steel structures

2016 ◽  
Author(s):  
Minoo Kabir ◽  
Didem Ozevin
Keyword(s):  
Periodic Structure ◽  
Crack Detection ◽  
Steel Structures ◽  
Detection Ability ◽  
Mems Sensor

Magnetic Images and NDT of the Express Train Wheel Using a High Speed Scan-Type Magnetic Camera

2009 ◽  
Vol 417-418 ◽  
pp. 169-172 ◽  
Author(s):  
Ji Seong Hwang ◽  
Jin Yi Lee
Keyword(s):  
High Speed ◽  
Crack Detection ◽  
Sensor Array ◽  
Hall Sensor ◽  
Limited Time ◽  
High Speed Train ◽  
Detection Ability ◽  
Express Train ◽  
High Crack ◽  
Magnetic Camera

Wheels are essential parts of an express train, as they support the train’s weight, but because of the limited time available for testing and repair in the maintenance factory, the 1000 wheels of each high-speed train must be tested within 1 h. Therefore it is essential to develop a new NDT system that is able to (a) detect cracks quickly and (b) provide high crack-detection ability regardless of the state of the materials. In this paper we propose a scan-type magnetic camera to satisfy this need. We use a linearly integrated Hall sensor array (LIHaS) as a magnetic sensor to make high-speed testing possible, and we use a small, yoke-type magnetizer as the magnetic source for the magnetic camera to assure high crack-detection ability. We tested the method by examining the cracks on a sample wheel traveling at 27.5km/h.

PERIODIC BOLT PLACEMENT IN STEEL STRUCTURES FOR GUIDED DAMAGE DETECTION

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Lu Zhang ◽  
Didem Ozevin ◽  
Gorkem Okudan
Keyword(s):  
Damage Detection ◽  
Frequency Response ◽  
Galvanic Corrosion ◽  
Steel Structures ◽  
Periodic Pattern ◽  
Behavior Changes ◽  
Vibration Modes ◽  
Bolted Connections ◽  
Detection Ability ◽  
Weakest Link

Connections form the weakest link in structural systems. Bolted connections are especially susceptible to stress corrosion cracking due to stress-riser points at the bolt edges and the intrusion of water between plates leading to galvanic corrosion. Bolts are conventionally placed based on minimum and maximum spacing requirements guided by American Institute of Steel Construction. Unfortunately, the detectability of crack and corrosion is currently not a design variable. In this study, bolts are placed in periodic pattern such that they exhibit unique frequency response. The periodic placement allows modeling only unit cell in the shape of hexagon with periodic boundary conditions to obtain the frequency response. When damage occurs, the periodic pattern is broken, and the frequency response behavior changes. The influence of crack to vibration modes is numerically modeled, and the damage detection ability with unique bolt placement is demonstrated. It is shown that the spatial distribution of bolt can assist the damage detection ability, which should be considered as a criterion in the design of bolted connections.

Micropatterning of Metal-Grid Micro Electro Mechanical Systems (MEMS) Sensor for Crack Detection Using Electrohydrodynamic Printing System

2020 ◽  
Vol 20 (7) ◽  
pp. 4385-4389 ◽  
Author(s):  
Yong-Chan Lee ◽  
Henzeh Leeghim ◽  
Chang-Yull Lee
Keyword(s):  
Optimum Condition ◽  
Crack Detection ◽  
Environmental Parameters ◽  
Micro Electro Mechanical Systems ◽  
Mems Sensor ◽  
Micro Cracks ◽  
Metal Grid ◽  
Electrohydrodynamic Printing ◽  
Printing System ◽  
Crack Position

In this paper, a mechanism of sensors for micro crack detection is proposed according to circuit disconnection. In order to detect micro cracks, sensitive sensors based on micropatterning using a electrohydrodynamic (EHD) technology are necessary. For EHD printing, it is essential to find an optimum condition between ink materials and environmental parameters. Therefore, the distribution of the jetting mode between the flow rate and the voltage is confirmed through experiments. Metal-grid was patterned and resistance of each circuit by crack occurrence was measured. The resistance changes are occurred at the position where the crack is generated, and the crack position can be estimated with grid type sensors. The resistance in the cracked circuits are relatively larger than it in non-cracked circuits. It was confirmed that micro cracks were well detected by using the proposed crack sensors and mechanisms.

P107 Fatigue Crack Detection in Steel Structures by Self-reference Lock-in Thermography

2005 ◽  
Vol 2005 (0) ◽  
pp. 637-638
Author(s):  
Takashi Nishimura ◽  
Takahide Sakagami ◽  
Shiro Kubo ◽  
Kazunari Ishino
Keyword(s):  
Fatigue Crack ◽  
Crack Detection ◽  
Steel Structures ◽  
Fatigue Crack Detection ◽  
Lock In ◽  
Self Reference

Risk Based Inspection Planning for Fatigue Damage in Offshore Steel Structures

2015 ◽  
Author(s):  
Tom Lassen ◽  
Naman Recho
Keyword(s):  
Crack Propagation ◽  
Crack Detection ◽  
Fatigue Cracks ◽  
Steel Structures ◽  
Life Extension ◽  
Inspection Time ◽  
Reliable Estimate ◽  
Practical Case ◽  
Fatigue Reliability ◽  
Inspection Planning

High fatigue reliability is one of the most important design criteria for welded offshore steel structures. Due to repeated wave loading fatigue cracks may initiate and grow in welded joints that are important for the integrity of these structures. The present paper presents the methodology and the practical calculations for risk based inspection planning for fatigue cracks in welded details. Due to the uncertainty in the variables involved in the problem the planning has to be carried out by stochastic modeling and risk based assessments. Scatter in potential crack growth has to be analyzed by applied probabilistic facture mechanics and the uncertainty in the performance of the actual inspection technique has to be determined. With given risk acceptance criteria the practical outcome of the analyses is recommended inspection techniques and associated planned inspection time intervals. The classical theory is outlined and the latest recommendations from a Joint Industry Project recently completed by Det Norske Veritas in Norway are discussed. Discussion on how to model the fatigue process correctly is emphasized, particularly the role of time to crack initiation versus the subsequent crack propagation phase. Proper modeling of these two phases is crucial to get the potential crack path correct and thus obtain a reliable estimate of the probability of crack detection. For the crack propagation phase the selection of geometry functions is addressed. A practical case study for life extension of an offshore oil loading system is finally presented. A structural significant item in the system is the steel gooseneck connection for the sub-sea flexible loading hoses. The case is an interesting one in the way that two similar systems were analyzed independently, one analysis based on the tradition S-N approach and one where the decisions were reliability based by applying the Risk Based Inspection approach.

Ship Hull Diagnostics with the Use of Remotely Operated Underwater Vehicle

NDT World ◽  
2015 ◽  
Vol 18 (3) ◽  
pp. 12-15 ◽  
Author(s):  
Третьяков ◽  
Evgeniy Tretyakov ◽  
Бритвин ◽  
Vladimir Britvin ◽  
Вельтищев ◽  
...  
Keyword(s):  
Crack Detection ◽  
Flaw Detection ◽  
Surface Preparation ◽  
Steel Structures ◽  
Ship Hull ◽  
Contact Method ◽  
Remotely Operated Vehicle ◽  
Sh Waves ◽  
Dry Dock ◽  
Diagnostics System

Introduction. Nowadays ship hull diagnostics is carried out in dry-dock or using divers in the road. The both technologies are time consuming, labour and material resource demanding. Specialists from Bauman Moscow State Technical University have developed a diagnostics system that allows the ship hull underwater part inspection to be performed without calling at dry-dock and without divers. The system includes the following main elements: remotely operated vehicle that contains diagnostics tools; hydro acoustic navigation system; software; and diagnostics technology. Method. The technology is based on an acoustic method of non-destructive testing (NDT). SH-waves with elastic vibrations excitation by non-contact method are used without necessity of thorough surface preparation before testing. SH-waves are also used for flaw detection within damaged areas (areas of different thicknesses). As the research has shown, the mirror-shadow technique with bottom signal attenuation as a criterion for corrosion crack detection is most effective. The minimum detectable deep of the corrosion cracks is 1.5–2 mm. The proposed diagnostics technology uses electromagnetic acoustic transducers (EMAT) with a 5 MHz frequency. Results. The diagnostics system was successfully tested in the pool. The test results confirmed the system’s ability to perform automatic metal diagnostics with wall thickness measurements and defect detection within areas of corrosion. Discussions. Nowadays the system is under the process of Russian Maritime Register of Shipping approval. It is planned to develop a system with arc welding tools for underwater objects repair. Prospects of diagnostics system usage for the various underwater steel structures including ones located on the Russian Federation Arctic shelf are under consideration.

Inspection of the Internal Cracks on a Pipe Using a Cylinder-Type Magnetic Camera

2009 ◽  
Vol 417-418 ◽  
pp. 165-168
Author(s):  
Jung Min Kim ◽  
Jin Yi Lee
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Crack Detection ◽  
Sensor Array ◽  
Solenoid Coil ◽  
Detection Ability ◽  
Mechanical Parts ◽  
High Crack ◽  
Magnetic Camera ◽  
The Magnetic Field

Two important factors in damage tolerance engineering are the damage size that can be tolerated and the use of applied nondestructive testing (NDT) technique for detection of defects. Generally, NDT of large mechanical structures, such as vessels and pipes in nuclear power plants, is carried out according to national codes, and the damaged mechanical parts detected during periodic NDT are repaired or replaced after the evaluation. However, unexpected accidents can occur if cracks in the structure grow and exceed the tolerance limit during operation. Therefore, there is a need to develop NDT techniques that can detect micro-damage in the vessels and pipes. In this paper, we propose a cylinder-type magnetic camera to fill this need. We use a cylindrically integrated Hall sensor array (CIHaS) as a magnetic sensor to create magnetic images, and we use a solenoid coil as the source of the magnetic field detected by the magnetic camera in order to achieve high crack-detection ability. The proposed method is tested with an examination of the cracks on a prepared pipe sample.

scholarly journals The effect of crack geometry on stiffness of spring steel cantilever beam

2018 ◽  
Vol 37 (4) ◽  
pp. 762-773 ◽  
Author(s):  
V Khalkar ◽  
S Ramachandran
Keyword(s):  
Free Vibration ◽  
Cantilever Beam ◽  
Crack Detection ◽  
Crack Depth ◽  
Steel Structures ◽  
Spring Steel ◽  
Cantilever Beams ◽  
Crack Location ◽  
Crack Geometry ◽  
Shaped Crack

The survival of the crack in structures always keeps the structure away from performing well in applications due to significant changes in its dynamic response. It has been observed that in service the size of the crack in structures increases with time and finally it leads to its catastrophic failure. Hence it is crucial to do the vibration study of cracked beams in regard of free vibration-based crack detection and its crack classification. Until now the vibration-based nondestructive testing methods are applied to many spring steel cracked cantilever beams for its possible crack detection. However, the effect of various kinds of practical cracks, i.e. V-shaped, U-shaped and rectangular-shaped open cracks, on the applicability of these methods has been overlooked. In order to investigate this issue, artificially cracks are made on the cantilever beam. By free vibration analysis, the effect of crack geometry, crack depth, and crack location on the beam stiffness is investigated. In this study, the stiffness of each cracked case is computed by the deflection methods and vibration methods to ensure the strong validation. The stiffness results obtained from V-shaped, U-shaped and rectangular-shaped crack models for the same configuration are compared with each other and it is found that the results of the stiffness are comparatively more sensitive to U-shaped crack models. Through vibration study, it is found that spring steel structures are slightly sensitive to the change in crack geometries as long as the vibration characteristics are concerned. Hence, it is obvious that free vibration-based crack detection method can satisfactorily predict the location and depth of the crack in any spring steel structures irrespective of the crack geometries. Apart from this, it is also found that for the same configurations, EN 8 and EN 47 cracked cantilever beams give the identical structural integrity or structural stability property for all the cracked cases. Lastly, it is also found that as the crack depth increases by keeping the crack location constant, the stiffness of the beam decreases.

Sign in / Sign up

Export Citation Format

Share Document