Experimental tests for the assessment of residual strength of r.c. structures after fire – Case study

2022 ◽  
Vol 252 ◽  
pp. 113681
Author(s):  
Giada Frappa ◽  
Margherita Pauletta ◽  
Caterina Di Marco ◽  
Gaetano Russo
Keyword(s):  
Residual Strength ◽  
Experimental Tests

Improving the Traditional RCA Methodology to Design a Most Efficient and Reliable Valve for LDPE Hypercompressors Leveraging Experimental Data From Test Bench Simulation: A Real Case Study

2013 ◽  
Author(s):  
Carmelo Maggi ◽  
Leonardo Tognarelli ◽  
Riccardo Bagagli ◽  
Jan Wojnar
Keyword(s):  
Failure Modes ◽  
Good Accuracy ◽  
Deep Understanding ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Gas Composition ◽  
Pressure Losses ◽  
Valve Operation

The behavior of the valves of Hypercompressors on LDPE plants is challenging to predict because it depends on many factors and often the expected and macroscopic gas parameters, such as pressure, temperature and gas composition are not sufficient to properly evaluate the valve behavior in the field. In fact valve operation is highly dependent on local phenomena such as localized pressure losses and presence of vortexes which are in turn influenced by the geometry of the valve and by its behavior. To better understand all these phenomena it is needed to characterize these valves through experimental tests aimed at defining, with a good accuracy, the valve dimensionless parameters Cd (drag coefficient) and Ks (flow coefficient) as a function of the geometry of the valve itself. If the coefficients Cd and Ks are not accurate, the expected behavior of the valve may be completely different from the evidence of the field and could not properly explain certain types of failure modes. With a more accurate evaluation of Cd and Ks, some types of damage which in first hypothesis would seem caused by factors external to the valve, in reality are proven to be intrinsically related to valve design and often dependent on valve malfunctioning. As a final step, through to a deep understanding of the valve behavior in the field an improvement of valve reliability and efficiency can be achieved through optimization of the design for various operating conditions.

Monitoring Data for Retrofit Assessment

2008 ◽  
Vol 56 ◽  
pp. 557-562
Author(s):  
Sara Casciati ◽  
Sebastiano Floridia ◽  
Nicola Impollonia ◽  
Enrico Reale
Keyword(s):  
Relative Efficiency ◽  
Experimental Tests ◽  
Monitoring Systems ◽  
Structural Systems ◽  
Numerical Studies ◽  
Load Carrying ◽  
Before And After ◽  
Complex Structural ◽  
Processing Techniques

A construction history that spans centuries often results in complex structural systems whose load-carrying behavior cannot be easily assessed by visual inspections. Their structural rehabilitation should be supported by numerical analyses during both the design and the implementation phases of a retrofit operation. Within this context, monitoring systems provide reliable information about the structure performance under serviceability conditions. When outputonly measurements are available for the dynamic system identification before and after the intervention, signals processing techniques can be applied to assess both the original deteriorated state of the structure, and the relative efficiency of the retrofit operation. The procedure is illustrated with reference to a specific case study, which concerns a part of the Archbishop Palace located in Siracusa, Italy. Experimental and numerical studies are carried out to evaluate the actual loads supported by an ancient stone arch. The arch is surmounted by a building which underwent several additions in elevation across the centuries. Experimental tests are performed using different excitation methods and accelerometer configurations. The measurements are taken before and after the retrofit of the arch. The elaboration and comparison of the collected data for the structural assessment of the system before and after its retrofit is the topic of this work.

scholarly journals Lighting conditions as the occupational health related issue – case study

2022 ◽  
Vol 354 ◽  
pp. 00059
Author(s):  
Luiza Dębska ◽  
Anita Białek
Keyword(s):  
Experimental Tests ◽  
Public Utility ◽  
Intelligent Building ◽  
Intelligent Buildings ◽  
Lighting Conditions ◽  
University Of Technology ◽  
Health Related ◽  
Different Seasons ◽  
Lighting Intensity

The paper deals with the important element of proper lighting conditions at a workplace. The case study has been focused on the intelligent building “Energis” of Kielce University of Technology, where the experimental tests took place. Several groups of volunteers filled in the questionnaires related to their subjective feelings of lighting conditions in lecture rooms at different seasons. Simultaneously, precise measurements of lighting intensity were carried out. The comparison of the expressions of the room users and the measurements enabled to draw conclusions about the conditions provided in the intelligent building related to lighting. The study provides valuable information of lighting conditions in the modern, intelligent buildings which are more and more common throughout the world and serve various purposes such as office, educational or other public utility buildings.

scholarly journals Modeling and Performance Assessment of the Split-Pi Used as a Storage Converter in All the Possible DC Microgrid Scenarios. Part II: Simulation and Experimental Results

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5616
Author(s):  
Massimiliano Luna ◽  
Antonino Sferlazza ◽  
Angelo Accetta ◽  
Maria Carmela Di Piazza ◽  
Giuseppe La Tona ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Storage System ◽  
State Space Model ◽  
Experimental Tests ◽  
Energy Storage System ◽  
Dc Microgrid ◽  
Voltage Generator ◽  
Control Scheme ◽  
And Performance

Bidirectional DC/DC converters such as the Split-pi can be used to integrate an energy storage system (ESS) into a DC microgrid providing manifold benefits. However, this integration deserves careful design because the ESS converter must behave like a stiff voltage generator, a non-stiff voltage generator, or a current generator depending on the microgrid configuration. Part I of this work presented a comprehensive theoretical analysis of the Split-pi used as an ESS converter in all the possible DC microgrid scenarios. Five typical microgrid scenarios were identified. Each of them required a specific state-space model of the Split-pi and a suitable control scheme. The present paper completes the study validating the theoretical analysis based on simulations and experimental tests. The chosen case study encompassed a 48 V, 750 W storage system interfaced with a 180 V DC microgrid using a Split-pi converter. It can represent a reduced-power prototype of terrestrial and marine microgrids. A prototypal Split-pi converter was realized in the lab, and several experimental tests were performed to assess the performance in each scenario. The results obtained from the experimental tests were coherent with the simulations and validated the study.

scholarly journals Wood and Its Impact on Humans and Environment Quality in Health Care Facilities

2019 ◽  
Vol 16 (18) ◽  
pp. 3496 ◽  
Author(s):  
Veronika Kotradyova ◽  
Erik Vavrinsky ◽  
Barbora Kalinakova ◽  
Dominik Petro ◽  
Katarina Jansakova ◽  
...  
Keyword(s):  
Positive Impact ◽  
Experimental Tests ◽  
Well Being ◽  
Health Care Facilities ◽  
Waiting Room ◽  
Respiration Activity ◽  
Environment Quality ◽  
Care Facilities ◽  
Volatile Organic Compound Emissions

The paper presents the application of natural materials, especially wood, which are relevant for human well-being in built environments of health, social, and day care facilities. These properties were tested by a complex methodology in a case study in the wooden waiting room at National Oncology Institute in Bratislava. In this space, experimental tests of physiological responses were further executed on 50 volunteers moving in the waiting room for 20 min. In this article, the EEG (electroencephalograph) (four persons) and emotions from the faces of all our volunteers before entering and after a stay in a wooden waiting room were recorded. Specifically, the ECG (electrocardiograph), heart rate (HR), and respiration activity were measured by using our own designed ECG holter (40 persons), and also blood pressure and cortisol levels were observed. The usage of wooden materials verifies their regenerative and positive impact on the human nervous system, through the appealing aesthetics (color, texture, and structures), high contact comfort, pleasant smell, possibility to regulate air humidity, volatile organic compound emissions (VOC-emissions), and acoustic well-being in the space.

Measuring the Young’s Relaxation Modulus of PDMS Using Stress Relaxation Nanoindentation

2009 ◽  
Vol 1222 ◽  
Author(s):  
Ping Du ◽  
Hongbing Lu ◽  
Xin Zhang
Keyword(s):  
Stress Relaxation ◽  
Reaction Force ◽  
Relaxation Modulus ◽  
Experimental Tests ◽  
Constitutive Law ◽  
Time Data ◽  
Flat Punch ◽  
Pdms Film ◽  
Bending Tests

AbstractThe Young’s relaxation modulus of Polydimethylsiloxane (PDMS) film specimens was measured by the nanoindenter with a flat punch indenter. In the stress relaxation test, the initial ramp part was carefully considered to develop an accurate viscoelastic contact model. This model was used to fit the load-time data from the experimental tests. The resulting relaxation function was expressed by a general Maxwell equation. In addition, a case study of PDMS micropillar bending tests was performed, and the viscoelastic constitutive law was applied to develop an analytical solution of the reaction force. The results show that the reaction force calculated from the corrected model is generally agreed well with the experimental data.

Case study: The effect of an amorphous hydrogenated carbon-coated gear-wheel on a hydraulic orbital motor’s efficiency over time

2018 ◽  
Vol 234 (3) ◽  
pp. 320-333 ◽  
Author(s):  
CA Bates ◽  
HW Broe-Richter ◽  
CR Bendlin ◽  
P Ennemark
Keyword(s):  
Energy Savings ◽  
Gear Wheel ◽  
Experimental Tests ◽  
Electron Microscopic ◽  
Before And After ◽  
Carbon Coated ◽  
Gear Wheels ◽  
Amorphous Hydrogenated Carbon ◽  
Over Time

This case study examines how the application of an amorphous hydrogenated carbon coating to gear-wheels affects the volumetric and mechanical efficiencies of the hydraulic orbital motors into which the gear-wheels are assembled. The efficiencies over time of these orbital motors are compared with the efficiencies of orbital motors, which were assembled and tested with standard (uncoated) gear-wheels. Comparisons are based on experimental data, accumulated over 3000 h of steady-state tests, divided over six motors with a duration of 500 h each. The paper examines the surface roughness characteristics of amorphous hydrogenated carbon-coated gear-wheels before and after coating, the measured magnitudes and positions of wear on the contact surfaces of the coated and uncoated gear-wheels after testing, and the observed differences in said wear utilizing scanning electron microscopic analyses. Finally, changes in the measured efficiencies of the orbital motors are examined, over the duration of the experimental tests, in order to consider the potential energy savings associated with hydraulic orbital motors assembled with coated gear-wheels.

scholarly journals Modelling Magnetorheological Dampers in Preyield and Postyield Regions

2019 ◽  
Vol 2019 ◽  
pp. 1-23 ◽  
Author(s):  
E. Palomares ◽  
A. L. Morales ◽  
A. J. Nieto ◽  
J. M. Chicharro ◽  
P. Pintado
Keyword(s):  
Experimental Tests ◽  
Magnetorheological Damper ◽  
Semiactive Control ◽  
Nonlinear Behaviour ◽  
Magnetorheological Dampers ◽  
Huge Number ◽  
Low Velocity ◽  
Highly Nonlinear ◽  
Control Schemes

The use of magnetorheological dampers has rapidly spread to many engineering applications, especially those related to transportation and civil engineering. The problem arises upon modelling their highly nonlinear behaviour: in spite of the huge number of apparently accurate models in the literature, most fail when considering the overall magnetomechanical behaviour. In this study, a brief but broad review of different magnetorheological damper models has been carried out, which includes characterisation, modelling, and comparison. Unlike many other studies, the analyses cover the behaviour from preyield to postyield regions of the MR fluid. The performance of the different models has been assessed by means of numerous experimental tests and by means of simulations in a simple and straightforward semiactive control case study. The results obtained prove that most models usually fail in predicting accurate low-velocity behaviour (before iron chains yield) and, as a result, may lead to bad estimations when used in control schemes due to modelling errors and chattering.

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