The Experts below are selected from a list of 1482 Experts worldwide ranked by ideXlab platform
Herdovics B - One of the best experts on this subject based on the ideXlab platform.
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Structural Health Monitoring (SHM) using torsional guided wave EMATs
'SAGE Publications', 2016Co-Authors: Fb Cegla, Herdovics BAbstract:Torsional guided wave inspection is widely used for Pipeline inspection. Most commonly piezoelectric and magnetostrictive transducers are used to generate torsional guided waves. These types of transducers require bonding or mechanical contact to the Pipe which can result in changes over time which are undesirable for Structural Health Monitoring. This paper presents a non-contact Lorentz force based Electromagnetic Acoustic Transducer for torsional guided wave monitoring of Pipelines. First, the excitation mechanism of the transducer is simulated by analyzing the eddy current and the static magnetic field using the finite element method. An EMAT transformer model is presented which describes the eddy current generation transfer function and the ultrasound excitation. Independently simulated eddy current and magnetic fields are used to calculate the Lorentz force that an EMAT array induces on the surface of a 3 inch Schedule 40 Pipe and an explicit finite element solver is then used to simulate the elastic wave propagation in the Pipe. Then, the reception mechanism and the expected received signal levels are discussed. The construction of an experimental transducer is described and measurement results from the transducer setup are presented. The measured and modeled performance agree well. Finally, a monitoring example is presented where an artificial defect with 3% reflection coefficient is introduced and successfully detected with the designed sensor
Joseph, Roshan Prakash - One of the best experts on this subject based on the ideXlab platform.
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Acoustic Emission and Guided Wave Modeling and Experiments for Structural Health Monitoring and Non-Destructive Evaluation
Scholar Commons, 2020Co-Authors: Joseph, Roshan PrakashAbstract:This dissertation is organized into major parts. In Part I of the dissertation, plate guided waves due to an acoustic emission (AE) event are analytically studied in the context of seismic moment tensor sources. The guided wave propagation elastodynamic equation corresponding to a point source applied to the plate in an arbitrary direction is modified in order to describe the case when the source is a seismic moment tensor of various tensor components. This part of the dissertation also discusses the analytical modeling of AE test sources such as pencil lead break, hammer hit excitation, etc. In Part II of the dissertation, in situ experimental investigation and predictive modeling of AE from fatigue crack is discussed. The fatigue-crack growth-related AE needs to be separated from crack rubbing/clapping AE to understand the signals originating from the crack and to comprehend the situation of the crack in real-time. Novel SIF-controlled fatigue-crack growth experiment and vibration-induced crack rubbing/clapping experiment was invented for this purpose. The fatigue AE signals were recorded using piezoelectric wafer active sensors (PWAS). The AE source due to fatigue crack growth and rubbing/clapping was assumed as components of the moment tensor source discussed in Part-I, and the simulation was performed. The simulation results were compared with experimental observations, and a good agreement of simulation and experiment was observed. Part III focuses on guided modeling of wave propagation in hollow cylinders. Normal mode expansion (NME) of hollow cylinder guided wave modes for a radial point source excitation is derived analytically. Mutually orthogonal guided wave modes in the hollow cylinder are used for NME, and the modal participation factors are determined analytically. Part IV focuses on the experimental and analytical investigation of health monitoring of hollow cylinders using the passive and active health monitoring techniques discussed in Part III. Both passive and active structural health monitoring experiments are done on the TN32 dry cask storage scaled-down model. Then, the SAFE-NME method discussed in Part III was also used for the predictive simulation in a ‘6-inch Schedule-40’ Pipe
Fb Cegla - One of the best experts on this subject based on the ideXlab platform.
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Structural Health Monitoring (SHM) using torsional guided wave EMATs
'SAGE Publications', 2016Co-Authors: Fb Cegla, Herdovics BAbstract:Torsional guided wave inspection is widely used for Pipeline inspection. Most commonly piezoelectric and magnetostrictive transducers are used to generate torsional guided waves. These types of transducers require bonding or mechanical contact to the Pipe which can result in changes over time which are undesirable for Structural Health Monitoring. This paper presents a non-contact Lorentz force based Electromagnetic Acoustic Transducer for torsional guided wave monitoring of Pipelines. First, the excitation mechanism of the transducer is simulated by analyzing the eddy current and the static magnetic field using the finite element method. An EMAT transformer model is presented which describes the eddy current generation transfer function and the ultrasound excitation. Independently simulated eddy current and magnetic fields are used to calculate the Lorentz force that an EMAT array induces on the surface of a 3 inch Schedule 40 Pipe and an explicit finite element solver is then used to simulate the elastic wave propagation in the Pipe. Then, the reception mechanism and the expected received signal levels are discussed. The construction of an experimental transducer is described and measurement results from the transducer setup are presented. The measured and modeled performance agree well. Finally, a monitoring example is presented where an artificial defect with 3% reflection coefficient is introduced and successfully detected with the designed sensor
Galvagni Andrea - One of the best experts on this subject based on the ideXlab platform.
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Pipeline health monitoring
Mechanical Engineering Imperial College London, 2014Co-Authors: Galvagni AndreaAbstract:Worldwide, BP operates many thousand kilometres of Pipelines carrying valuable yet toxic and corrosive fluids. The structural integrity of these Pipelines is crucial, as any failure may result in environmental damage, economic losses and injuries to personnel. Convention- ally, Pipeline integrity is assessed on a time basis. This inherently limits the amount of infor- mation available about its structural health, as any damage which develops in unexpected circumstances or while the Pipeline is not being inspected may remain undetected. Such lack of information hinders the reliability of any prognosis and of Risk-Based Inspection and Maintenance strategies, increases the risk of unexpected critical damage development and Pipeline failure, and forces the use of costly time-based maintenance, following the safe-life design approach. Conversely, if sufficient information about Pipeline integrity were avail- able to produce reliable prognoses, then it would become possible to dramatically reduce the risk of unexpected failures and to utilise cost-efficient condition-based maintenance, which prescribes the replacement of a Pipeline only when it is about to suffer critical dam- age and has therefore reached the actual end of its operational life. In this way, Pipeline networks would become safer and more reliable while at the same time more productive and less costly. This thesis introduces and demonstrates a Structural Health Monitoring ap- proach that has the potential to fill the integrity information gap and ultimately enable the use of condition-based Pipeline maintenance. This approach, embodied by a practical au- tomated Pipeline damage detection procedure, complements permanently installed guided wave sensors to create a complete Pipeline health monitoring solution. Utilising experimen- tal data from a permanently installed guided wave sensor installed on a purpose-built NPS 8 Schedule 40 Pipe loop facility at BP’s Naperville Campus, it is shown that the procedure is very effective at detecting and quantifying actual damage, thereby achieving the intended aim of this thesis.Open Acces
Magfiroh Yesty - One of the best experts on this subject based on the ideXlab platform.
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Studi Kelayakan Harga Perolehan Gas CNG Di Pulau Bawean Sebagai Pengganti HSD Untuk Pembangkit Listrik Tenaga Mesin Gas
2015Co-Authors: Magfiroh YestyAbstract:Kebutuhan energi listrik di Indonesia terus meningkat seiring meningkatnya pertumbuhan ekonomi. Kebutuhan listrik yang semakin tinggi menjadi tantangan bagi pemerintah serta PLN yang merupakan pemasok listrik dalam negeri.Salah satu defisit ekonomi Indonesia dikarenakan impor negara masih lebih tinggi, terutama untuk minyak. Solusi terbaik untuk menyelesaikan problem ini adalah melakukan diversifikasi energi dari bahan bakar minyak ke bahan bakar gas. Bahan bakar gas terutama CNG sangat cocok diterapkan di Indonesia. Salah satunya Pulau Bawean. Pulau Bawean yang disuplai 4 unit PLTD dengan menggunakan BBM HSD rencananya akan diganti dengan BBG CNG untuk PLTMG.Untuk itu perlu dibangun fasilitas penyediaan gas di pulau Bawean. Pembangunan beberapa fasilitas harus dihitung secara cermat baik dari segi teknik maupun ekonomi. Proses analisa dilakukan secara teknik dan ekonomi. Dimulai dengan perhitungan konsumsi listrik di Pulau Bawean,pertimbangan daya tertinggi untuk pemilihan genset,perhitungan sfc genset, perhitungan kebutuhan gas di Pulau Bawean,perhitungan gas yang akan dibawa ke Bawean, perhitungan spesifikasi spesifikasi peralatan utama seperti compressor, CNG storage, Kapal pengangkut, Skid di Bawean, Pressure Reducing System. Kemudian dilanjutkan dengan analisa secara ekonomi dengan menggunakan kriteria Biaya investasi dan biaya operasi. Dari analisa ini didapatkan spesifikasi peralatan utama PLTMG diantaranya: CNG Kompresor Temperatur masuk 30o c, Tekanan masuk 2Mpa, daya 567,89 kw, kapasitas 4831,6 NCMH, CNG Storage kapasitas berat total 29888 kg, tekanan kerja 25 MPA, temperatur kerja -40oc-60oc, PRU tekanan masuk 250 bar, tekanan keluar 3 bar; spesifikasi kapal LOA 48 meter lebar 9 m, tinggi 3,5 meter, main engine 2x405HP, spesifikasi pipa ke kompresor diameter 3 in dan Schedule 40; spesifikasi pipa dari kompresor ke skid adalah diameter pipa 1 in Schedule xxs; spesifikasi pipa dari dermaga ke daughter station adalah diameter pipa 1 in Schedule xxs. Harga perolehan gas di Pulau Bawean yakni Rp 10.381,00 lebih murah dibandingkan dengan harga 1 liter HSD yang berkisar Rp 11 060,27. =============================================================================================== Electrical energy in Indonesia continues to increase with increasing economic growth. The higher demand for electricity become a challenge for the government and PLN which is a supplier of electricity in Indonesia.One of the economic defisit in Indonesia because the country imports is still higher , particularly for oil . The best solution to resolve this problem is to diversify energy from fuel oil to gas fuel . Especially CNG fuel gas is very suitable to be applied in Indonesia. Bawean island supplied four diesel power units using HSD fuel planned to be replaced with CNG for PLTMG. It is necessary to build facilities for the supply of gas in Bawean island . Construction of some facilities must be calculated in both technical and economic analysis. The process includes the technical and economic analysis. Starting with the calculation of power consumption in the Bawean island , using the highest power to selection the gas engine, calculate specific fuel consumption of gas engine , calculation of gas which needs in Bawean Island a day , calculation of gas that will be taken to Bawean , calculation of specifications of major equipment such as compressor , CNG storage , transport vessels, Pressure Reducing System. Then proceed with the economic analysis using the criteria of investment costs and operating costs . The results obtained from this analysis are the spesification of CNG Compressor are inlet temperature 30 ° C , Inlet pressure 2Mpa , power 567.89 kw, capacity of 4831.6 NCMH ; CNG storage , total weight of 29 888 kg,working pressure 25 MPA , the working temperature -40oc -60oc; PRU inlet pressure of 250 bar , the outlet pressure 3 bar ; vessel specifications LOA 48 meters width 9 m , height of 3.5 meters , the main engine Yanmar 2x405HP , Pipe diameter specifications, from gas tapping to compressor are 3 in and Schedule 40 ; Pipe specifications from the compressor to skid is diameter of the Pipe 1 in and Schedule XXS ; Pipe specification from the skid in vessel to the daughter station is diameter of the Pipe 1 in and the Schedule XXS . The acquisition price of gas for Bawean Island is Rp 10 381,00. This is cheaper than the price of 1 liter HSD ,Rp 11 060,2
