This research focuses on the verification of the viability of image compression in infrared thermography in order to address the problem of data storage. Specifically, images from vibrothermographic tests were utilized due to their special characteristics compared to the results from alternative infrared thermography techniques, which are able to introduce additional uncertainties to the compression

Refractory metals are favorable materials in applications where high strength and ductility are needed at elevated temperatures. In some cases, operating temperatures may be near the melting point of the material. However, as temperature drops, refractory metals typically undergo a significant mechanical response change - ductile-to-brittle transition. These materials may be subjected to high strain

In the original article, the first author A. Paul Praveen’s name was mentioned incorrectly in the author list. The details given in this correction are correct.

In the last years, the wind industry has increased in a large scale. A wind turbine out of service leeds to high costs due to both maintenance and repair costs and the incapability of producing electricity. A substantial part of the wind turbine failures are in the drivetrain, mainly in generator and gearbox. Several recent works focuses in the study of benefits of the integration of condition monitoring

Hybrid simulation (HS) and real-time HS (RTHS) are widely used experimental techniques to evaluate the seismic performance of structural components and full systems. The goal of this study is to investigate the performance and limitations of RTHS when the computational model involves complex and highly nonlinear behavior, mainly due to both stiffness and strength deterioration. To establish the case

The characteristics of superelasticity and shape-memory of the NiTi make endodontic rotary files suitably flexible and resistant while operating within curved canals. However, continuous rotation within accentuated curvatures causes stresses that can lead to intraoperative fracture by torsional shear or flexural cyclic fatigue. The aim of this paper is to design and build a rotary bending testing machine

The constant velocity one-dimensional wave theory has been commonly used to determine the pile lengths from the impulse response testing results for several years. In this paper, the three-dimensional guided wave theory was introduced to extract more information from the impulse response spectra on five concrete piles. Combined with resonance concept, this guided wave-based approach was developed to

Control is a critical element in many applications and research such as experimental testing in real-time. Linear approaches for control and estimation have been widely applied to real-time hybrid simulation (RTHS) techniques in tracking the physical domain (plant). However, nonlinearities and highly uncertainties of the plant impose challenges that must be properly addressed using nonlinear control

To experimentally assess the fire resistance of civil structures, testing whole structures is very costly but the standard tests on individual structural elements can sometimes be too simplistic, regarding their boundary conditions. Hybrid fire testing is then a promising approach to overcome some of these limitations. In order to perform such tests, the existing procedures make use of estimated parameters

Anemometric method is the most accurate and reliable technique for air velocity measurement. In present work, a voltage follower based circuit is proposed, and a low-cost sensor (tungsten filament) is chosen to perform Constant Voltage Anemometer (CVA) operation for air velocity measurement. For performing the real-time experiment, a wind tunnel featuring a rectangular section (test section I) and

Uncertainties in real-time hybrid simulation include structural parameters and ground motion. Uncertain parameters often do not follow common distribution types. Data-driven arbitrary polynomial chaos constructs optimal orthogonal polynomial basis based on the sample data without distribution assumption. In this study, the data-driven polynomial chaos is compared with other generalized polynomial chaos

Real-time hybrid testing is a technology which allows the coupling of simulations and component tests in order to simulate complex system dynamics. Delays and time lags caused by actuator dynamics and signal processing deteriorate the stability of the tests in many cases. The application of adaptive feedforward filters to hybrid testing enables circumventing this problem. The stability of the filter

In this study, the applicability of yield criteria and flow curve models to predict forming limit curve (FLC) via the Marciniak-Kuczynski (M-K) model is investigated for TWIP900 steel. Forming limit characteristics of TWIP900 are determined experimentally and numerically. The yield criteria of Hill48, Barlat89, YLD2000-2d, and BBC2000 are tested and compared with each other. Results indicate that the

The aim of this paper is to provide an insight into the effect of fine content (FC) on the artificially cemented gravel-silty clay mixed soils (CMS) in terms of strength, deformation, effective stress path and pore pressure response by undrained cyclic triaxial tests. In addition, some cyclic triaxial tests were also conducted on remolded gravel-silty clay mixed soils (RMS) under the same test conditions

Widely used in earthquake engineering, Hybrid testing is promoted in various domains such as wind engineering, coastal structures and fluid-structure interaction. It also begins to be applied to fire engineering (Hybrid Fire Testing or HFT) for coupling fire tests and numerical simulations. However, HFT is still in its infancy. Yet, some tests have been performed and some algorithms have been developed

A new device that enables the application of controlled mechanical loads to devitalized cortical bone blocks in liquid media mimicking physiological environment is described. In the setup, it is possible to evaluate elimination of calcium from a bone during the exposure to slightly acidic media in the presence or absence of periodic controlled mechanical load. In the test experiments with the fragments

Cyber-physical empirical methods enable to address problems that classical empirical methods alone, or models alone, cannot address in a satisfactory way. In CPEMs, the substructures are interconnected through a control system that includes sensors and actuators, having their own dynamics. The present paper addresses how the fidelity of CPEMs, that is the degree to which they reproduce the behaviour

Early detection of bearing defects may prevent the occurrence of catastrophic failures of the whole associated system. Condition monitoring strategies such as vibration and acoustic signal analyses are employed for incipient fault diagnosis of bearings. The current investigation attempts to compare the fault diagnostic capabilities in terms of their effectiveness in early detection of local bearing

Hybrid simulation (HS) is an experimental technique possessing advantages over other testing methods and, in several cases, it is the only available method to test structural systems with reliability. In this paper, HS is used to assess the effects of upgrading a soft-storey frame building using a Buckling-Restrained Brace (BRB). This topic is of paramount significance in seismic regions like Mexico

To be able to track the deformation of fibers in composite laminates subject to high strain bending and to study any changes that occur due to elevated temperature hold, an experimental technique using micron scale X-ray computed tomography (micro-CT) was developed and is reported here. A lab based X-ray micro-CT system with resolution as low as 0.7 μ m was used to scan an approximately 0.76 × 0.76

Demand of higher speeds in rotor systems has elevated the possibility of numerous instabilities. Internal damping is one of the key parameters for instability in such machinery. Its studies are generally conducted for a possible range of chosen internal damping values. Hence, experimental estimation of internal damping along with external damping is very vital for an accurate prediction of rotor stability

An automatic discontinuous deformation measurement (DDM) approach was proposed to evaluate full-field deformations during the crack propagation process based on the digital image correlation (DIC) method. The color speckle pattern and crack identification procedure were applied at first in the DDM approach to obtain the region of interest (ROI) in the speckle images, the DIC analysis was then used

Assessment of operating loads is often approached as an inverse process using vibration response data and some form of system model to reconstruct external forces. Any mismatch in dynamic behavior between the model and the real system may distort the estimated loads. However, if the changes in system behavior are of interest, then those changes may be characterized through force reconstruction as equivalent

The Brazilian disc test has been used widely to measure the tensile strength of brittle materials, such as rock and ceramic. However, the Brazilian disc method developed for rock has not been applicable for nuclear graphite due to the large ratio of tensile to compressive strength in the material. According to the results of stress analysis and Griffith’s strength criteria, the graphite compressive

Traditional techniques to derive dynamic specification for components have a great deal of uncertainty. One of the major sources of uncertainty is that the number of response measurements in the operational system environment is insufficient to determine the component motion. This inadequacy is due to logistical limitations for data recording in field testing and space limitations for accelerometers

One-time operational modal analysis (OMA) of large civil structures requires measurements of the vibrations, which, according to the number of channels to be measured, are generally expensive and arduous to obtain. In this study, identification of modal parameters of civil structures has been investigated by using multiple setups with a roving reference channel. In this manner, a limited amount of

Dynamic substructuring (DS) is a research field that has gained a great deal of attention in both science and industry. The aim of DS techniques is to provide engineers in structural vibrations and sound practical solutions for analyzing the dynamic behavior of complex systems. This paper addresses the singularity problem that occurs when flexible joints are implemented as substructures into the Lagrange

Multi-shaker vibration testing is gaining interest from structural dynamics test engineers as it can provide a much more accurate match to complicated field vibration responses than traditional single-axis shaker tests. However, the force capabilities of the small modal shakers typically used in multi-shaker vibration tests has limited the achievable response levels. To date, most multi-shaker vibration

A method for estimation of rubber bushing stiffness parameters is presented. Four individual rubber bushings, mounted in a car rear subframe are considered. A traditional model of the bushing elements using a generalised spring model, known as a CBUSH element in Nastran, is compared to a geometrically more realistic approach where the bushing is modelled with solid elements and a linear elastic material

Load redistribution in smart load bearing mechanical structures can be used to reduce negative effects of damage or to prevent further damage if predefined load paths become unsuitable. Using controlled friction brakes in joints of kinematic links can be a suitable way to add dynamic functionality for desired load path redistribution. Therefore, adequate friction models are needed to predict the friction

In this article, the dynamics of a double-acting pneumatic actuator was experimentally studied. To understand the details of dynamics and provide experimental data for further modeling and numerical simulation of actuators, a special test bench was designed. The bench includes a high-resolution linear encoder as well as a dSPACE 1104 data acquisition board, that permits high-frequency sampling to identify

Experimental study on scheme optimization of composite damping structure was carried out and the effect of environmental temperature on damping characteristic was investigated in the present study. Damping coefficient of three layers composite damping structure is nearly ten times of that of light plate. The scheme of composite damping structure has a significant effect on damping characteristic. Effect

Cavitation is an important problem that occurs in any pump and contributes highly towards the deterioration in the performance of the pump. In industrial applications, it is vital to detect and decrease the effect of cavitation in pumps. In this study therefore, focus is on detecting and diagnosing the cavitation phenomenon within a centrifugal pump using vibration technique. The results obtained for

Measuring accurate dynamic deformation distribution for large-scale structures inexpensively and efficiently is a crucial challenge of structural health monitoring. In this study, a simple technique for measuring the deflection and vibration frequency from a captured video, based on the sampling Moiré method is developed. The striking advantage over conventional measurement using sensors and other

In order to understand the mechanism of fixed-point rub-impact in aero-engine, a dual-rotor system with inter-shaft bearing able to describe the mechanical vibration caused by unbalance and fixed-point rub-impact is developed in this paper. Firstly, a finite element (FE) model of the dual-rotor based on Timoshenko beam element and disk element is proposed, in which the effects of gyroscopic moments

In order to avoid the measurement error brought by heating before aerodynamic heating tests in a hypersonic wind tunnel, it’s essential that the testing model should be insert into the flow field quickly. This paper presents a novel fast-moving device driven by a hydraulic system which was based on gas-liquid boosting cylinder and servo proportional valve. The control system of the fast-moving device

For flight payloads or systems in free flight, Impedance Matched Multi-Axis Testing (IMMAT) can provide an accurate laboratory reproduction of the flight vibration environment at multiple response locations. IMMAT is performed by controlling multiple shakers attached to the system of interest, usually through slender rods so that the shakers impart negligible moments or shear forces at the attachment

Material strength under complex stress states is vital for structure design. This paper studied the strength and failure behaviour of 3D C/C composites under compression-shear coupled loads. Experiments were conducted using a modified anti-symmetric four-point bending (MAFPB) method and off-axis compression method. Two dominant failure modes were observed; 1) shear and 2) compression. Mode transitions

Electrochemical Micromachining is a unique kind of non-traditional machining practice for the production of micro and nano features. This paper aims to measure and assess the performance and geometrical features of ECMM on SS304 alloy by influencing the effect of different types of electrolytes viz.; Passivating, Non-Passivating and Composite electrolyte (CPE). Material removal rate (MRR), circularity

Shock wave dynamics is a topic with a wide variety of applications ranging from removal of kidney stones to inertial confinement fusion. In reality, the shock front is most often followed by a decay in flow properties, and therefore it is of interest to better understand shock dynamic events for these situations. Thus, an experimental facility that can provide results that are accurate, highly controlled

A test method based upon a Hybrid-III head and neck assembly that includes measurement of both linear and angular acceleration is investigated for potential use in impact testing of protective headgear. The test apparatus is based upon a twin wire drop test system modified with the head/neck assembly and associated flyarm components. This study represents a preliminary assessment of the test apparatus

Engineering elastic constants and strength parameters shall be known to the designer in order to predict the structural response of composite materials. These properties shall be determined in various directions as per the designated standards. Testing of composite materials under the combined effect of in-plane shear and normal stress is of great importance. In this work, a new Arcan fixture has been

In this work, novel Linear Discriminant Analysis (LDA) based indicator has been developed for the detection of unbalance and misalignment at different shaft speeds. The process started with the acquisition of shaft displacement data in fixed time increment. Adaptive resampling of the acquired data was carried to convert time domain data to angular domain. Further, spectrum of angular domain signal

Mycelium is a biopolymer that has the potential to be a sustainable replacement for petroleum based foams in some engineering applications. During a recent study, with the objectives to first relate the effects of growing conditions on material properties and second to develop a model to predict the bulk behavior of mycelium, it was found that a variety of standard test methods are being used for the

This paper presents a regression analysis of uniaxial and multiaxial fatigue life for automobile coil spring under various road excitations. Coil spring is a suspension component with complex geometry and shear loading which is applied during operating conditions. Hence, uniaxial strain measurement for durability assessment of coil spring is insufficient because the loadings are non-proportional. Rosette

This paper presents a modified, Michelson Interferometer based single camera digital shearography setup which enables simultaneous measurement of multiple shearing directions. Digital shearography is a non-contact, high precision, anti-turbulence optical approach for testing of minor deformation gradients. As a measuring instrument, however, its application is limited, due to its reliance on the shearing

In recent years, stringent environmental regulations for air pollution have led to increased demand for liquefied natural gas (LNG). Therefore, the demand for the design and construction of LNG-fueled vessels has also increased. One of the most important points for the design of LNG-fueled vessels is the structural integrity of the LNG fuel tank, particularly at cryogenic temperatures. Low temperature

Digital Image Correlation (DIC) is a well-established, non-contact diagnostic technique used to measure shape, displacement and strain of a solid specimen subjected to loading or deformation. However, measurements using standard DIC can have significant errors or be completely infeasible in challenging experiments, such as explosive, combustion, or fluid-structure interaction applications, where beam-steering

This study includes an experimental study of a buoyant jet in an open channel. For this reason experiments to measure the mean axial velocity at the centreline of a buoyant jet which is discharged vertically upwards from a source, into a denser fluid (water) contained in an open channel a) without flow and b) into flowing environment, were performed. The presence of a buoyant jet is studied experimentally

Rock bolts are widely used in the main structure of the DC transit system and play the role of the main body reinforcement and support. Because of the extensive stray current in the subway system, the corrosion risk of rock bolts is greatly increased. Therefore, the rock bolt was experimentally studied by simulating the input stray current and monitoring the polarization potential in this paper. After