Three-dimensional stress measurement for structural steel plates using ultrasonic T-waves and P-waves

In this study, the effects of experimental parameters on average surface roughness and material removal rate (MRR) were experimentally investigated by machining of AISI 304 stainless steel plates by magnetic abrasive finishing (MAF) method. In the study in which three different abrasive types were used (Al2O3, B4C, SiC), the abrasive grain size was changed in two different levels (50 and 80[Formula: see text][Formula: see text]m), while the machining time was changed in three different levels (30, 45, 60[Formula: see text]min). Surface roughness values of finished surfaces were measured by using three-dimensional (3D) optical surface profilometer and surface topographies were created. MRRs were measured with the help of precision scales. The abrasive particles’ condition before and after the MAF process was examined and compared using a scanning electron microscope. As a result of the study, the surface roughness values of plates were reduced from 0.106[Formula: see text][Formula: see text]m to 0.028[Formula: see text][Formula: see text]m. It was determined that the best parameters in terms of average surface roughness were 60[Formula: see text]min machining time with 50[Formula: see text][Formula: see text]m B4C abrasives, while the best result in terms of MRR was taken in 30[Formula: see text]min with 50[Formula: see text][Formula: see text]m SiC abrasives.

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Intermeshing: A New Concept For Rapid Steel Erection

IABSE Congress, New York, New York 2019: The Evolving Metropolis ◽

10.2749/newyork.2019.0187 ◽

2019 ◽

Author(s):

Salam Al-Sabah ◽

Debra Laefer ◽

Linh Truong-Hong

Keyword(s):

Structural Steel ◽

Three Dimensional ◽

Steel Bridges ◽

Digital Manufacturing ◽

Initial Analysis ◽

Contact Points ◽

Steel Connection ◽

Welding Forces ◽

And Robotics ◽

Steel Cutting

<p>Three-dimensional intermeshing of steel enabled by advanced digital manufacturing holds the potential to radically change how steel bridges and buildings are connected. This paper presents the concept of the first universal structural steel connection in over 100 years. The proposed Intermeshed Steel Connection (ISC) exploits recent advances in steel cutting technologies and robotics to shape member ends precisely. This vastly reduces on-site bolting and welding. Forces are transferred through common bearing surfaces at multiple contact points. The new connection is designed to accelerate structural steel deployment and offer better disassembly options. This paper introduces the geometry, manufacturing, and initial analysis of the connection approach, which holds the potential to be robust, secure, scalable, and faster to erect.</p>

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FEA of SAW penetration of Ramor 500 steel

Materials Testing ◽

10.1515/mt-2020-621207 ◽

2020 ◽

Vol 62 (12) ◽

pp. 1192-1198

Author(s):

Ali Kaya Gur ◽

Semih Taskaya ◽

Subramaniam Shankar ◽

Thangamuthu Mohanraj

Keyword(s):

Three Dimensional ◽

Welding Process ◽

Source Model ◽

Strength Properties ◽

Steel Plates ◽

Constant Current ◽

Welding Seam ◽

Depth Increase ◽

Thermal Cooling ◽

Submerged Arc

Abstract Ramor 500 steel plates are used as a ballistic material due to their greater hardness and strength properties. This steel can be produced with a 2-30 mm thickness sheet which may attain 505-590 HV hardness. In the present work, Ramor 500 steel pairs are joined using a submerged arc welding (SAW) process and taking various parameters into consideration. An austenitic additional wire is used for the welding process which contains Cr, Ni, and Mn. The source model prototype was developed using ANSYS software and considering a time-dependent three dimensional thermal model with source cooling. The highest tensile stress voltage value was determined in the sample applying a constant current of 250 A, 25 V and 30 cm × min-1welding speed. It was observed that the welding seam width increases as welding tension grows and that welding height and depth increase and decrease more or less in tandem. A ANSYS thermal cooling analysis revealed that welding tension grows with heat transfer which increases 15 mm from the main center of the welding area.

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Absolute stress measurement of structural steel members with ultrasonic shear-wave spectral analysis method

Structural Health Monitoring ◽

10.1177/1475921717746952 ◽

2017 ◽

Vol 18 (1) ◽

pp. 216-231 ◽

Cited By ~ 9

Author(s):

Zuohua Li ◽

Jingbo He ◽

Jun Teng ◽

Qin Huang ◽

Ying Wang

Keyword(s):

Spectral Analysis ◽

Structural Steel ◽

Shear Wave ◽

Wave Amplitude ◽

Stress Measurement ◽

Amplitude Spectrum ◽

Uniaxial Stress ◽

Wave Pulse ◽

Steel Members ◽

Pulse Echo

Absolute stress in structural steel members is an important parameter for the design, construction, and servicing of steel structures. However, it is difficult to measure via traditional approaches to structural health monitoring. The ultrasonic time-of-flight method has been widely studied for monitoring absolute stress by measuring the change in ultrasonic propagation time induced by stress. The time-of-flight of the two separated shear-wave modes induced by birefringence, which is particular to shear waves, is also affected by stress to different degrees. Their synthesis signal amplitude spectrum exhibits a minimum that varies with stress, which makes it a potential approach to evaluating uniaxial stress using the shear-wave amplitude spectrum. In this study, the effect of steel-member stress on the shear-wave amplitude spectrum from the interference of two shear waves produced by birefringence is investigated, and a method of uniaxial absolute stress measurement using shear-wave spectral analysis is proposed. Specifically, a theoretical expression is derived for the shear-wave pulse-echo amplitude spectrum, leading to a formula for evaluating uniaxial absolute stress. Three steel-member specimens are employed to investigate the influence of uniaxial stress on the shear-wave pulse-echo amplitude spectrum. The testing results indicate that the amplitude spectrum changes with stress and that the inverse of the first characteristic frequency in the amplitude spectrum and its corresponding stress exhibit a near-perfect linear relationship. On this basis, the uniaxial absolute stress of steel members loaded by a test machine is measured by the proposed method. Parametric studies are further performed on three groups of steel members made of 65# steel and Q235 steel to investigate the factors that influence the testing results. The results show that the proposed method can measure and monitor steel-members uniaxial absolute stress on the laboratory scale and has potential to be used in practical engineering with specific calibration.

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Physiological ECG Value for Polish Half-Bred Anglo-Arab Horses

Bulletin of the Veterinary Institute in Pulawy ◽

10.2478/v10213-012-0111-4 ◽

2012 ◽

Vol 56 (4) ◽

pp. 631-635 ◽

Cited By ~ 1

Keyword(s):

Heart Rate ◽

P Wave ◽

P Waves ◽

T Wave ◽

Duration Time ◽

Qt Intervals ◽

Electrocardiographic Examination ◽

Electrocardiographic Findings ◽

Almost All ◽

T Waves

Abstract The electrocardiographic examination was performed in 33 training horses (2-16 years of age, 11 males and 22 females). Einthoven and precordial leads (I, II, III, aVR, aVL, aVF, CV1, CV2, CV4) were used. The ECG was performed in resting horses and immediately after exercise (10 min walk, 15 min trot, 10 min canter) using a portable Schiller AT-1 3-channel electrocardiograph, with a paper speed of 25 mm sec-1 and a sensitivity of 10 mm.mV-1. The heart rate, wave amplitudes, and duration time were estimated manually. All horses presented a significant increase in heart rate after exercise (rest 43.83 ±10.33 vs. exercise 73.2 ±14.8). QT intervals were significantly shortened in most of the leads. In resting horses, all P waves in the lead I were positive and almost all II, III and CV4 leads were positive. Simple negative P wave dominated in aVR and only simple negative T wave was found in the leads I. The biphasic shape was observed. After exercise, the amplitude of P and T waves rose, however, clear changes were not observed in wave polarisation and form. In the absence of specific racial characteristics of the electrocardiogram in the Polish Anglo- Arabians, electrocardiographic findings can be interpreted according to ECG standards adopted for horses.

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Vehicle Body and Roll Cage Assessment involving Frontal, Side and Roll-over Crash Analysis by FEA using LS-Dyna

International Journal of Vehicle Structures and Systems ◽

10.4273/ijvss.13.4.18 ◽

2021 ◽

Vol 13 (4) ◽

Author(s):

V. Hariram ◽

K. Venkatesh ◽

M. Venkata Saidev ◽

M. Surisetty Mahesh ◽

M. Vinothkumar ◽

...

Keyword(s):

Carbon Fiber ◽

Structural Steel ◽

Three Dimensional ◽

The Body ◽

Vehicle Body ◽

Crash Analysis ◽

Steel Members ◽

Vehicle Collision ◽

Six Degree Of Freedom ◽

Frontal Side

Simulating the vehicle collision has gained importance in the automotive sector due to its accuracy, cost effectiveness and enhanced reliability. It aids in improving the safety of driver and passenger and also examine the cause of crash or collision. This numerical analysis investigates the materials capability to enhance safety. A three-dimensional vehicle model was developed along with its roll cage using solid work tool. Hypermesh work bench was employed to discretise the sensitive parts of the body and roll cage using beam 189 element having six degree of freedom at each node. The existing structural steel members were replaced with reinforced carbon fibre in all the sensitive part of the body and roll cage and its structural stability was assessed using the frontal, side and roll over crash simulation using LS Dyna. This investigation also reveals the change in internal energy, kinetic energy absorption and momentum transfer for both structural steel and carbon fiber under all the crash scenarios. The outcomes of this numerical investigation proved that the reinforced carbon fiber can be effectively replaced with the structural steel to enhance safety.

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Structural Steel Plates

Handbook of Comparative World Steel Standards, 5th Edition ◽

10.1520/mnlds67d20160003 ◽

2016 ◽

pp. 47-106

Keyword(s):

Structural Steel ◽

Steel Plates

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Industrial Photogrammetry—Its Application to Shipbuilding

Marine Technology and SNAME News ◽

10.5957/mt1.1988.25.3.229 ◽

1988 ◽

Vol 25 (03) ◽

pp. 229-236

Author(s):

Michael J. Gunn ◽

Ronald S. Hicks

Keyword(s):

Structural Steel ◽

Three Dimensional ◽

Practical Applications ◽

Physical Objects

Photogrammetry is the science of acquiring and interpreting three-dimensional data of physical objects by measuring and analyzing their images on photographic plates. The development of this technology since the mid-seventies has increased its credibility for application to industrial and shipbuilding use. Analytical photogrammetry is now routinely employed in shipbuilding for tasks as diverse as predicting the fit-up of structural steel assemblies prior to their joining, verifying the circularity of submarine hulls, and checking the alignment of catapult trough components on aircraft carriers. The authors address the practical applications of photogrammetric technology, and identify the reliability, versatility, and productivity of photogrammetric surveying when applied to shipbuilding.

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Electrocardiography

Oxford Textbook of Medicine ◽

10.1093/med/9780198746690.003.0342 ◽

2020 ◽

pp. 3294-3314

Author(s):

Andrew R. Houghton ◽

David Gray

Keyword(s):

Myocardial Infarction ◽

Electrical Activity ◽

19Th Century ◽

Diagnostic Tool ◽

Posterior Aspect ◽

P Waves ◽

Right Ventricular Myocardial Infarction ◽

The 19Th Century ◽

Ventricular Depolarization ◽

T Waves

The electrocardiograph (ECG) has been recognized as a valuable diagnostic tool since the end of the 19th century. The normal ECG waveform consists of P, QRS, and T waves (and sometimes U waves)—P waves result from atrial depolarization, QRS complexes from ventricular depolarization, and T waves from ventricular repolarization. The standard 12-lead ECG utilizes four limb electrodes and six precordial electrodes to generate 12 leads or ‘views’ of the heart’s electrical activity. There are six limb leads (termed I, II, III, aVR, aVL, and aVF) and six precordial leads (termed V1, V2, V3, V4, V5, and V6). Supplementary ‘views’ can be obtained by using additional leads, such as V7, V8, and V9 to assess the posterior aspect of the heart and right-sided chest leads to look for a right ventricular myocardial infarction.

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