Journal articles on the topic 'Structural failures – Investigation'
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Barone, Pier, and Rosa Di Maggio. "Forensic Investigations of Geohazards: The Norcia 2016 Earthquake." Geosciences 8, no. 9 (August 23, 2018): 316. http://dx.doi.org/10.3390/geosciences8090316.
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Earthquakes represent one of the world’s most significant hazards in terms of damage to human and animal life, and property. Earthquakes also cause many other related fatalities and damage to urban structures. This paper presents the forensic investigation of failures induced by the Norcia 2016 earthquake in Italy. The detailed geophysical field investigations were carried out at selected locations in two cities: Rome and Amelia. The places of investigation were 150 km and 90 km, respectively, from the epicenter. A ground penetrating radar (GPR) survey was carried out at the sites to highlight structural failures, and included a partially damaged urban bridge, and the cracked wall of a private house. These failures have been discussed with reference to the field measurements carried out. In both cases, the GPR radargram showed clear lesions along with their geometry and location. This forensic geoscientific analysis highlights the importance of detecting structural damage immediately after a geohazard event to help plan proper interventions, efforts to prevent human losses and help law enforcement to focus their forensic investigations.
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Zhang, Weihua, Pingbo Wu, Xuejie Wu, and Jing Zeng. "An investigation into structural failures of Chinese high-speed trains." Engineering Failure Analysis 13, no. 3 (April 2006): 427–41. http://dx.doi.org/10.1016/j.engfailanal.2004.12.037.
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Chhetri, Sandip, Rachel A. Chicchi, and Andrew E. N. Osborn. "Experimental investigation of 0.6 in. diameter strand lifting loops." PCI Journal 66, no. 2 (2021): 71–87. http://dx.doi.org/10.15554/pcij66.2-03.
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Very little experimental data have been published relating to the pullout capacity of prestressing strand lifting loops. To address this gap in knowledge, 13 pullout tests were conducted on strand lifting loops with 0.6 in. (15.24 mm) diameter, 270 ksi (1860 MPa) strand. Straight and bent orientations were tested for single loops at different embedment depths. Loops were embedded in 12 in. (304.8 mm) wide and 44 in. (1117.6 mm) deep concrete blocks and subjected to monotonic, static loading until failure. Marginal bond quality of the strand (18.2 kip [81 kN]), Mohs hardness (3.6), and concrete strength (3000 psi [20.7 MPa]) resulted in an average bond stress value of 400 psi (2758 kPa) at failure. Most tests exhibited pullout failure modes and adequate ductility. Three loops tested at 32 in. (812.8 mm) embedment with 6 in. (152.4 mm), 90-degree bends experienced brittle side-face blowout failures. These failures were due to inclination of the lifting, which led to a reduced edge distance. A safe uniform bond stress of 199 psi (1372 kPa) is recommended for 0.6 in. diameter strand.
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Liu, Yi-Fen, and I.-Ling Ling. "Keep fighting or give up? An investigation of consumer regret over repetitive failures in weight loss services." Journal of Services Marketing 36, no. 1 (November 29, 2021): 29–43. http://dx.doi.org/10.1108/jsm-12-2020-0499.
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Purpose Weight loss services feature high consumer involvement that is sometimes marked by repetitive failures. These features can affect regret and its associated factors differently from the way that discrete failure can. The purpose of this study is to investigate consumer regret over repetitive failures in weight loss services as well as its antecedents (overeating and insufficient exercise), consequences (rumination and reflection) and moderators (failure experiences and required effort). This study also investigates how rumination and reflection affect persistence intention. Design/methodology/approach A total of 318 samples were collected through three surveys, one of which contained a scenario, provided to consumers who experienced repetitive failures in weight loss. The proposed relationships were tested using structural equation modeling, dominance analysis and PROCESS modeling. Findings The results of this study reveal that overeating contributes to regret more saliently than does insufficient exercise. The effect of regret on rumination (thoughts about continuing to blame oneself and giving up the pursuit of goals) is stronger than on reflection (thoughts about learning from prior failures and willingness to try again), and greater reflection results in higher persistence intention. Moreover, the effect of insufficient exercise on regret and the effect of regret on rumination are augmented with cumulative failure experiences, whereas required effort enhances the impact of regret on reflection. Originality/value This study is the first to focus on regret over repetitive failures in weight loss. It advances the literature by clarifying the antecedents and consequences of regret, showing how failure experiences influence the relationships between regret and its associated factors as well as identifying interventions that benefit from regret.
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Rao, V. Bhujanga, R. Rajendran, A. V. Jaykumar, and K. H. B. S. Satyanarayana. "Metallurgical Investigation of HSLA Steel Subjected to Underwater Explosion." Shock and Vibration 1, no. 4 (1994): 385–94. http://dx.doi.org/10.1155/1994/375854.
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The metallurgical behaviour of HSLA steel subjected to underwater explosion is of prime importance because of its structural applications in underwater vehicles. HSLA steel plates 300 × 250 × 4 mm were subjected to single and repetitive shock loadings and the point of rupture was identified. Test plates exhibited mode-I (large ductile deformation) and mode-II (tensile tearing) macroscopic failures. Electron micrographic and fractographic examination showed that the initiation of fracture was due to adiabatic shearing and the microscopic mode of failure was ductile. Plates subjected to single shock showed an increase in residual hardness and at the point of rupture it was approximately one-third higher than the initial residual hardness.
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Halvoník, Jaroslav, and Lucia Majtanová. "Experimental Investigation of the Maximum Punching Resistance of Slab-Column Connections." Slovak Journal of Civil Engineering 26, no. 3 (September 1, 2018): 22–28. http://dx.doi.org/10.2478/sjce-2018-0017.
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Abstract Flat slabs represent a structural system with a typical concentration of shear forces near the vicinity of its local supports. A possible failure from punching is a dangerous phenomenon due to the brittleness and possible progressive collapse of a whole structure. An improvement in the structural behaviour of a slab-column connection provides transverse reinforcement. The amount of this reinforcement and thus its contribution to the resistance against punching has a limit, which is represented by the maximum punching capacity. This capacity can be assessed using the kmax factor or by direct verification of the strut capacity. The article deals with the results of a test campaign carried out on flat slab specimens with their transverse reinforcements designed in such a way that the crushing of the struts is the governing mode of any failure. The test results obtained allowed for an evaluation of the kmax factors and provide an answer as to whether it is possible to cover failures due to the crushing of struts by this factor.
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Pavlov, Alexander Nikolaevich. "Investigation of structural reliability of P-networks with independent and dependent elements failures." SPIIRAS Proceedings, no. 11 (March 17, 2014): 81. http://dx.doi.org/10.15622/sp.11.4.
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Bagbanci, M. Bilal. "Investigation of installation systems and structural failures of Ottoman baths in Bursa, Turkey." International Journal of Academic Research 5, no. 3 (May 28, 2013): 213–18. http://dx.doi.org/10.7813/2075-4124.2013/5-3/a.30.
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Hou, Yongdan, Lemuel Gbologah, Derrick Boateng Asante, and Parpah Senanu Kwawukume. "Compositional and Structural Deficiencies Causing Failure of Local Fire Assaying Crucibles in Ghana." International Journal of Engineering Research in Africa 51 (November 2020): 57–70. http://dx.doi.org/10.4028/www.scientific.net/jera.51.57.
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Locally produced crucibles in Ghana experience dimensional failures during fire assaying of ores, therefore, even with a higher cost, imported crucibles are still the most preferred choice by laboratories in Ghana because of the stable performance of up to three cycles. Assay crucibles of locally manufactured, imported and theoretically composed were sampled and analysed via reverse engineering to identify factors that are attributed to the failure during use. Field investigation and compositional, physical and structural investigations were carried out using XRD, water boiling and SEM-EDS analyses, respectively. The results indicated that failure of the local crucible can be attributed to low mullite phase in both content and planes, which could ease the crack development and enhance the thermal stability of the crucible; non converted quartz into cristobalite, which stabilises the volume expansion coefficient during the fire assaying cycles; excess quartz content and absence of alumina content weakened the corrosion resistance against attack from the basic flux of litharge; and high porosity, allowed penetration of molten charge into the structure of crucible, leading to the dissolution of free silica content into the charge and causing structural failure. To overcome such deficiencies, higher firing temperature (~1240 °C), extra soaking time, and blending of high alumina contained clay/minerals were suggested.
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Debnath, Jhuma, Ajay Kumar, and Hrishikesh Sharma. "Numerical investigation of Reinforced-concrete beam-column joints under contact and close-in blast application." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 1203–8. http://dx.doi.org/10.38208/acp.v1.641.
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The behavior of the concrete and the steel material under blast loads are different. They have different mode of failures under blast loads. Also, responses differ according to the blast types concerning the proximity of the charge kept. It causes different failure modes in the structural members. Close-in or contact blast causes the spallation of concrete. In the near-field blasts, it causes bending failure in the structural members. The behavior of the mode of failure of various joint types subjected to contact-blast and close-in blast loads are numerically studied here. Three different joints simulated to carry on blast loads—exterior beam-column joint, interior beam-column joint, and knee joint simulated numerically under the close-in and contact loads. The charge for the contact blasts were applied to the joint is placed in contact with the joint core, and was not put at the beam or the column member of the joint cut section. In the current work, the failure behavior and the response of the RC beam-column joints is concluded.
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Adhikari, Rabindra, Pratyush Jha, Lalit Bhatt, Dipesh Thapa, Davide Forcellini, and Dipendra Gautam. "Failure Investigation of under Construction Prestressed Concrete Bridge in Chitwan, Nepal." Infrastructures 7, no. 2 (January 24, 2022): 14. http://dx.doi.org/10.3390/infrastructures7020014.
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On 6 April 2021, a 200 m-long under-construction prestressed concrete bridge failed in the Chitwan District in central Nepal. Two of the four bridge spans collapsed without any notable evidence of dynamic force application. Under-construction bridge failures are sometimes reported and can have a significant impact on the future construction adjustments. Thus, a detailed study of failure mechanisms will be insightful for the structural engineering community. Aiming to document the failure modes and exemplify lessons for improvement, this paper reports the detailed component level failure mechanisms of the bridge using visual inspection, site measurements, finite element modeling, and some forms of non-destructive testing. The chronological failure mechanisms are presented based on the field evidence and juxtaposed with the results of analytical modeling. The sum of findings highlights that the dead load failure, triggered by the settlement of falseworks, is the most critically governing factor that initiated and aggravated the damage scenario.
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Paripour, Mohammad Bagher, Ahmet Budak, and Oğuz Akın Düzgün. "Numerical investigation of reinforced concrete frame behavior subjected to progressive collapse." Challenge Journal of Structural Mechanics 4, no. 3 (September 4, 2018): 117. http://dx.doi.org/10.20528/cjsmec.2018.03.005.
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Progressive collapse is defined as the spread of an initial local failure of a structure. This phenomenon, caused by the removal of one or more load-bearing element, is followed by a chain of failures through the structure and ultimately leads to partial or even full collapse of an entire structure. As a result, an accurate understanding of structural behavior subjected to large displacements, caused by progressive collapse, is essential to ensure a safe structural design. A progressive collapse in buildings often starts with the removal of one or more columns and continues with the collapse of adjoining structural elements. Experimental studies on progressive collapse are generally not recommended because of its cost and safety reasons. Today, as a result of progress in computer technology, more complicated problems can be investigated numerically. In this study, a numerical model is used for nonlinear analysis of a reinforced concrete (RC) frame behavior subjected to progressive collapse. It is obtained that there is a good agreement between the results with those of the experimental study given in the literature. According to the results, it can be predicted numerically the response of an RC frame to progressive collapse at a highly accurate level.
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Papán, Daniel, and Zuzana Papánová. "Experimental investigation of the seismic effects during blasting works." MATEC Web of Conferences 313 (2020): 00019. http://dx.doi.org/10.1051/matecconf/202031300019.
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The interested part of dynamic analysis is the blasting work effects propagation through soil. This type of the dynamic load can be significant when the soil structure dynamic interaction hasn´t favourable conditions. It can cause structural failures on buildings. The main aim of the paper is to investigate how we can estimate the magnitudes of the seismic waves during blasting works. The results are based on experimental studies.
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Kopp, Gregory A., Emilio Hong, Eri Gavanski, Derek Stedman, and David M. L. Sills. "Assessment of wind speeds based on damage observations from the Angus (Ontario) Tornado of 17 June 2014." Canadian Journal of Civil Engineering 44, no. 1 (January 2017): 37–47. http://dx.doi.org/10.1139/cjce-2016-0232.
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A tornado occurred in Angus, Ontario, during the late afternoon hours of 17 June 2014. The authors conducted a damage investigation on the morning following the storm. The damage indicators support the classification of the tornado as an EF-2 on the Enhanced Fujita Scale, including the observation of several complete roof failures of recently-constructed, wood-frame houses. Most of the damage to residential homes was contained along two streets, with the tornado appearing to have gone down the backyards between the two. In total, 101 houses were observed to have sustained some level of damage. The evidence suggests that the quality of construction likely affected the performance of failed roofs. A detailed fragility analysis was conducted to assess wind speeds associated with these failures of the roof-to-wall connections. An overturned and lofted box truck provided the opportunity to correlate this failure with adjacent, repetitive failures of roof sheathing, shingles, and garage doors.
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Lin, Deng-Fong, and Her-Yuan Wang. "Forensic Investigation of Ultra-Thin Whitetopping Failures in Taiwan." Journal of Performance of Constructed Facilities 19, no. 2 (May 2005): 165–71. http://dx.doi.org/10.1061/(asce)0887-3828(2005)19:2(165).
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Rajapakse, Chathura, Hervé Degée, and Boyan Mihaylov. "Investigation of shear and flexural failures of dapped-end connections with orthogonal reinforcement." Engineering Structures 260 (June 2022): 114233. http://dx.doi.org/10.1016/j.engstruct.2022.114233.
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Khan, Muhammad Yousaf, Saad B. Qaisar, Muhammad Naeem, Awais Aslam, Saleem Shahid, and Ijaz Naqvi. "Detection and self-healing of cluster breakages in mines and tunnels: an empirical investigation." Sensor Review 35, no. 3 (June 15, 2015): 263–73. http://dx.doi.org/10.1108/sr-08-2014-0684.
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Purpose – The study aims at providing a reliable system of real-time monitoring for underground mine and tunnels which detects any structural change in the network and reconfigures it for resuming the data delivery process. In high stress environments, e.g. underground mines and tunnels, real-time activity monitoring is an emerging issue. Wireless sensor networks (WSNs) play a key role in ensuring the safety of people working in underground mines and tunnels. WSN not only provide real-time monitoring of underground environment but also detects any structural change in the network itself. Design/methodology/approach – In this paper, results of empirical implementation of a re-configurable WSN, capable of self-healing approach, reconfigure the network connectivity upon failure or addition of nodes in the system. An open-source radio-frequency identification standard for WSN, named as DASH7, is used for practical implementation. The proposed system is capable of determining cluster breakage by sudden disruptions caused by roof falls, explosions and node failures, sensor coverage hole, node re-addition to the network and distress priority signal generation by the miner. Findings – The proposed platform contributes to re-attain network state for establishing a communication link with fusion center in terms of: instant and accurate detection of collapse holes, acceptable error rate, time to re-attain network state, rapid distress signal propagation and low deployment cost. This platform is deployed in four different environments of anechoic chamber, hallway, outdoor and underground mine environment, to test the aforementioned scenarios using DASH7-compatible Bitsense Sensor Motes operating at 433 MHz. The effectiveness of the proposed approach has been experimentally validated for the single and multiple adjacent and disjoint node failures in all the four environments. Originality/value – The number of monitoring systems was implemented for safety assurance in high stress environments before, but the novelty of our platform is long range, cost effectiveness, quick response to any structural change in the network, rapid and accurate data delivery using WSN operated on DASH7 protocol stack.
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Angeletti, Federica, Paolo Iannelli, Paolo Gasbarri, Massimo Panella, and Antonello Rosato. "A Study on Structural Health Monitoring of a Large Space Antenna via Distributed Sensors and Deep Learning." Sensors 23, no. 1 (December 29, 2022): 368. http://dx.doi.org/10.3390/s23010368.
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Most modern Earth and Universe observation spacecraft are now equipped with large lightweight and flexible structures, such as antennas, telescopes, and extendable elements. The trend of hosting more complex and bigger appendages, essential for high-precision scientific applications, made orbiting satellites more susceptible to performance loss or degradation due to structural damages. In this scenario, Structural Health Monitoring strategies can be used to evaluate the health status of satellite substructures. However, in particular when analysing large appendages, traditional approaches may not be sufficient to identify local damages, as they will generally induce less observable changes in the system dynamics yet cause a relevant loss of payload data and information. This paper proposes a deep neural network to detect failures and investigate sensor sensitivity to damage classification for an orbiting satellite hosting a distributed network of accelerometers on a large mesh reflector antenna. The sensors-acquired time series are generated by using a fully coupled 3D simulator of the in-orbit attitude behaviour of a flexible satellite, whose appendages are modelled by using finite element techniques. The machine learning architecture is then trained and tested by using the sensors’ responses gathered in a composite scenario, including not only the complete failure of a structural element (structural break) but also an intermediate level of structural damage. The proposed deep learning framework and sensors configuration proved to accurately detect failures in the most critical area or the structure while opening new investigation possibilities regarding geometrical properties and sensor distribution.
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Chai, Teck Jung, Cher Siang Tan, and Shahrin Mohammad. "Structural performance of half scissor-like elements deployable structure." E3S Web of Conferences 347 (2022): 01005. http://dx.doi.org/10.1051/e3sconf/202234701005.
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An experimental investigation on the Half Scissor-Like Elements (H-SLEs) mechanism deployable structure under compression axial load is presented. Two prefab cylindrical shape H-SLEs mechanism deployable steel structures namely M1 (Bolted base column) and model M2 (Unbolted base column) were tested on their performance in term of strength and stability performance. The model prototype consists coldformed and hot roll steel with bolted connection and tested at deployed vertical configuration. Compression axial load was applied at the middle top of loading platform, transferred equally to the six H-SLEs deployable mechanism through supporting beams. The experimental results obtained indicated that three types of failure modes, i.e. excessive bearing capacity failure at lipped C-section flange around bolt hole perimeter, instability due to horizontal displacement at mid-height of H-SLEs deployable mechanism (Bolted joint area) and member buckling. Among these failures, horizontal displacement nominated the overall structure stability while section thickness impacts member bucking and bearing capacity. The experimental ultimate load was 1.63% greater than BS EN 1993 design load resistance for M1 condition while 30% less for M2 condition. The applied load difference between these two model prototypes was 31.15%. Thus, M1 ultimate loads capacity was satisfactory since less than 15% acceptable level while M2 not satisfactory. Beside, horizontal displacement was identify highly impacted scissor mechanism deployable structure instability and suitable member thickness may avoid section premature failure.
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Abashin, Victor G., Т. V. Charchenko, and А. B. Ilyin. "Cytogenetical aspects of miscarriages and reproductive failures at assisted fertilization technologies." Journal of obstetrics and women's diseases 52, no. 1 (January 20, 2003): 72–77. http://dx.doi.org/10.17816/jowd88803.
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It is known that chromosomal abnormalities are one of the most important causes of the spontaneous abortions. In this review we have considered the cytogenetical disturbances which can lead to miscarriages and embrio losses at assisted fertilization technologies. We have analyzed the structure of chromosome aberrations in spontaneous abortions and influence of the different types of alterations on the forecasting the future pregnancy outcomes. It has been considered the probability of recurrence of the pregnancy losses in patients-carriers of structural balanced chromosome rearrangements. In vitro fertilization implantation failures like as the miscarriages can depend on presence of chromosome anomalies including the occasions when the parents are the carriers of structural unbalanced rearrangements. So the kariotyping of couples, which require the assisted fertilization technologies, should be the necessary part of preliminary investigation.
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Vučetić, Nikola, Gordana Jovičić, Branimir Krstić, Miroslav Živković, Vladimir Milovanović, Josip Kačmarčik, and Ranko Antunović. "Further investigation of the repetitive failure in an aircraft engine cylinder head - Mechanical properties of Aluminum alloy 242.0." Mechanics 26, no. 4 (September 15, 2020): 285–92. http://dx.doi.org/10.5755/j01.mech.26.4.24556.
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Aluminum alloys are widely used in military and aviation industry due to their properties such as low density and high strength. During the aircraft operation there are mechanical failures of various structural components caused by numerous mechanisms such as corrosion, material defects, high cycle fatigue and the like. One of the frequent mechanical failures on air-cooled piston engines is the cylinder head cracking. This paper is the continuation a comprehensive research of the Lycoming IO-360-B1F aircraft cylinder head failure. The failure of this type has already occurred during flight and about 50 failures like this have been registered from around the world, some of them with a fatal outcome and therefore require detailed research. The paper consists of machining of the tested specimens and their testing at many different locations and in many different laboratories throughout Bosnia and Herzegovina, Serbia and Slovenia. This paper is based on a research that includes the experimental analysis of mechanical properties of Aluminum alloy 242.0 which is a constituent material of the cylinder head of the Lycoming IO-360-B1F aircraft engine on which a crack appeared. Based on chemical, metallographic, static and dynamic experimental tests of the material properties, Aluminum alloy 242.0 static and fatigue properties were obtained, S-N curve was formed and endurance limit was determined. Results of numerical simulations of experiments, confirmed by experimental results, were performed to make numerical procedures reliable due to further research. The results of the research are planned to be implemented in numerical modeling of the cylinder assembly stress-strain state under workload and in further numerical research of Lycoming IO-360-B1F cylinder assembly integrity assessment.
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Podestà, S., F. Romis, and L. Scandolo. "CONSOLIDATION AND RESTORATION OF HISTORICAL HERITAGE: THE FLAVIAN AMPHITHEATER IN ROME." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIV-M-1-2020 (July 24, 2020): 543–50. http://dx.doi.org/10.5194/isprs-archives-xliv-m-1-2020-543-2020.
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Abstract. The recovery and retrofitting techniques adopted for historical structures and archaeological sites face an apparent dichotomy between conservation of constructions and the safety of users. Literatures show several examples where the current day structural safety of historical constructions, gets defined by the nature of past interventions, the compatibility of materials and elements used in retrofitting. The adopted interventions were, in their time, considered innovative, but over the years their compatibility and reversibility leave the historic constructions structurally vulnerable. For these reasons, a careful understanding of the structural systems is fundamental for the implementation of appropriate retrofitting solutions. Especially for monuments and Archaeological sites the objective to be achieved has to be clear, avoiding destructive investigation tests. In this work the instabilities caused by a consolidation intervention on some travertine columns in a sector of the Flavian Amphitheatre, better known as “Colosseum” in Rome, are critically analysed. The current consolidation operations are compared to the previous one. The restoration activity involves in-depth diagnosis process: the historical analysis of the failures and restorations of that area of the Colosseum, a survey of the crack pattern and an indirect investigation on the travertine of the columns. Subsequently the various data coming from the knowledge phase are elaborated, in order to have a correct interpretation of the causes triggering the failure and guide the choice of the most correct retrofitting techniques.
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Aghamelu, O. P. "A geotechnical investigation on the structural failures of building projects in parts of Awka, southeastern Nigeria." Indian Journal of Science and Technology 4, no. 9 (September 20, 2011): 1119–24. http://dx.doi.org/10.17485/ijst/2011/v4i9.28.
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Sharma, Keshab, Mandip Subedi, Indra Prasad Acharya, and Bigul Pokharel. "Geotechnical and Structural Aspect of 2015 Gorkha Nepal Earthquake and Lesson Learnt." Journal of the Institute of Engineering 13, no. 1 (June 22, 2018): 20–36. http://dx.doi.org/10.3126/jie.v13i1.20345.
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An earthquake of moment magnitude (Mw ) 7.8 struck the central Nepal at 11:56 am on April 25, 2015. More than 9,000 people were killed and thousands of residential buildings, and hundreds other structures were also destroyed. An aftershock of moment magnitude (Mw ) 7.3 hit northeast of Kathmandu on May 12 after 17 days of main shock which caused additional damages. Immediately after the earthquake, authors undertook a field investigation and visited the affected areas. Strong motion records from both earthquakes and their impacts on structures as well as geotechnical issues are presented in this paper. Most of the structures in Nepal are made of adobe, unreinforced masonry, and reinforced concrete. Failure mechanisms of those buildings are briefly explained in this paper. Geotechnical aspects such as soil liquefaction, slope failures, settlement and lateral spreading, and site amplification effects that considerably influenced the damage patterns at many areas are briefly discussed as well. The lessons learnt from this earthquake are also summarized in this paper.Journal of the Institute of Engineering, 2017, 13(1): 20-36
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Gadalov, V. N., O. M. Gubanov, D. S. Alymov, and V. M. Roshchupkin. "Investigation and analysis of kinetic regularities of wear of internal surfaces of equipment under conditions of intense corrosion using different working media." Glavnyj mekhanik (Chief Mechanic), no. 8 (July 15, 2021): 62–75. http://dx.doi.org/10.33920/pro-2-2108-05.
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The reasons for failures of technological equipment made of structural steels during long-term operation in various environments and fields of application are considered. Investigations of the intensity of wear of equipment failures through the rate of damaging processes are presented. Modeling the processes of wear and tear of steel equipment, its failures was carried out using regression and correlation analyzes. The results of diagnostics are presented in accordance with the theoretical principles of statistical analysis, experiment in the form of polynomial kinetic wear models. The results of comparison of experimental and theoretical data on the wear rate for various types of equipment are also presented. The results of the normal distribution of the experimental values of the degree of wear for various types of equipment are shown, which is confirmed by the general uniform corrosion.
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Gadalov, V. N., O. M. Gubanov, D. S. Alymov, and V. M. Roshchupkin. "Investigation and analysis of kinetic regularities of wear of internal surfaces of equipment under conditions of intense corrosion using different working media." Glavnyj mekhanik (Chief Mechanic), no. 8 (July 15, 2021): 62–75. http://dx.doi.org/10.33920/pro-2-2108-05.
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The reasons for failures of technological equipment made of structural steels during long-term operation in various environments and fields of application are considered. Investigations of the intensity of wear of equipment failures through the rate of damaging processes are presented. Modeling the processes of wear and tear of steel equipment, its failures was carried out using regression and correlation analyzes. The results of diagnostics are presented in accordance with the theoretical principles of statistical analysis, experiment in the form of polynomial kinetic wear models. The results of comparison of experimental and theoretical data on the wear rate for various types of equipment are also presented. The results of the normal distribution of the experimental values of the degree of wear for various types of equipment are shown, which is confirmed by the general uniform corrosion.
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Dasandara, Miyami, Rusiru Ernst, Udayangani Kulatunga, and Pavithra Rathnasiri. "Investigation of Issues in Structural Flood Management Measures in Sri Lanka." Journal of Construction in Developing Countries 27, no. 1 (June 2022): 65–78. http://dx.doi.org/10.21315/jcdc2022.27.1.4.
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Floods can be identified as one of the devastating natural phenomena, which resulted in a considerable amount of social, economic and environmental impacts. Sri Lanka is a country that is highly vulnerable to floods due to its unique geographical location and topography. Many flood management measures, which mainly include structural and nonstructural have implemented to reduce the impact of floods. Among them, structural measures play a vital role in flood management. However, the failures in achieving the expected performance of these existing structural measures urge the need to identify issues with them and overcome those issues to enhance the flood management process in Sri Lanka. Hence, this study focused to investigate the issues related to structural flood management measures in Sri Lanka to bridge this knowledge gap. Initially, a literature review was conducted to gain a theoretical understanding of the research area. The research approach was qualitative, which was followed by two in-depth case studies. Semi-structured interviews were conducted with 10 industry experts to gather data. Collected data were analysed via content analysis. Empirical research findings revealed that structural measures play a prominent role in flood management. However, significant issues such as ageing of structural measures, leakages, construction faults, inadequate capacity, blocking of water flow and possibility of collapsing were identified in these existing structural flood management measures, which negatively impact the effectiveness of the overall flood management process within the country. The findings of this study will lead to gain a proper understanding of gaps and weaknesses in structural flood management measures in Sri Lanka and would influence the policymakers and other respective practitioners in disaster management to enhance structural flood management by using their novel ideas and concepts.
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Current, T. A., G. F. Kogler, and D. G. Earth. "Static structural testing of trans-tibial composite sockets." Prosthetics and Orthotics International 23, no. 2 (August 1999): 113–22. http://dx.doi.org/10.3109/03093649909071622.
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The purpose of this investigation was to quantify the structural strength of various trans-tibial composite sockets. To conduct the study, loading parameters and methods were developed that emulate the International Standards Organisation (ISO) standards for structural testing of lower limb prostheses since specific guidelines for the testing of the trans-tibial socket portion of a prosthesis have not yet been established. The experimental set-up simulated the instant of maximum loading during the late stance phase of gait. Ten trans-tibial sockets were evaluated. Five different reinforcement materials and two resin types were used to construct the sockets. A standard four hole distal attachment plate was used to connect the socket and pylon. Each sample was loaded to failure in a servo-hydraulic materials test machine at 100 N/s. None of the composites in the study met the ISO 10328 standards for level A100, loading condition II (4025 N), as required for other prosthetic componentry. All failures occurred at the site of the pyramid attachment plate. Ultimate strength and failure type were material dependent. Load point deflection was significantly different for the resin variable (p < 0.05). Statistical differences according to reinforcement material were noted in composite weight and strength-to-weight ratio (p < 0.05). The fibre volume fraction was also estimated and recorded. Reinforcement material type was the primary determinant of performance for the tested samples. Carbon reinforcements performed better than fibreglass reinforcements of similar weave type. The greatest ultimate strength and strength-to-weight ratio was observed with the unidirectional carbon reinforcement.
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Luo, Y. F. "The Burdened Area as a Structural Indicator of Interface Bonding Strength." Journal of Engineering Materials and Technology 120, no. 2 (April 1, 1998): 137–42. http://dx.doi.org/10.1115/1.2807002.
Full textAbstract:
In laminate structures, the interface debonding failures usually result from very complex fracture mechanisms which lead to different strengthening approaches. The bonding strength of two dissimilar bodies depends, to a great extent, on the bulk materials and the bonding structure in addition to the intrinsic interface adhesion. The structural effect on bonding strength will be emphasized in this investigation. The analysis will exhibit the relationship of materials, structures, and interface adhesion which is essential in understanding the failure mechanisms. This paper proposes that the burdened area on an interface is, according to experimental and analytical results, a structural indicator for bonding strength. Such a comprehensive parameter makes it easy to determine the complex contributions of so many structural parameters to the bonding strength. Although there are many microscopic observations of separated surfaces which support the concept of burdened area, a direct measurement of the burdened area is difficult in practice. Therefore an analytical or numerical evaluation is necessary. The solutions from the classical equation of elastic plate will be used to determine the distribution of interface stress as well as the size of burdened area. The bonding strength is considered as fracture toughness which is directly related with the burdened area. As a useful indicator for evaluating the bonding strength, the burdened area includes the effects of many structural parameters and mechanical properties, such as: elastic modulus, Poisson’s ratio, layer thickness, slanting angel, and corner radius. Burdened area is a property of structure because it is independent of the peeling loads, the material’s yielding strength and interface adhesion. As far as energy release rate is concerned, the boundary load is virtually distributed on the whole burdened area. The concept of burdened area will facilitate mechanical design of bonding strength and leads to a better understanding of various debonding failures.
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Khan, Mohammad Sadik, Masoud Nobahar, and John Ivoke. "Numerical Investigation of Slope Stabilization Using Recycled Plastic Pins in Yazoo Clay." Infrastructures 6, no. 3 (March 18, 2021): 47. http://dx.doi.org/10.3390/infrastructures6030047.
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Geographically, at the center of Mississippi is a concentration of High Plastic Yazoo Clay Soil (HPYCS). Shallow landslides frequently occur in embankments constructed with HPYCS caused by rainfall-induced saturation of the embankment slope. The traditional methods are becoming expensive to repair the shallow slope failure. The use of Recycled Plastic Pins (RPPs) to stabilize shallow slope failures offers a significant cost and construction benefit and can be a useful remedial measure for these types of failures. The current study investigates the effectiveness of RPP in slopes constructed with HPYCS, using the Finite Element Method (FEM). The FEM analysis was conducted with the PLAXIS 2D software package. Three uniform and varied RPP spacings were investigated to reinforce 2–4H:1V slopes. Reinforced slope stability analyses were performed to investigate the applicability of RPP in HPYCS. The FEM analysis results indicated that RPP provides shear resistance for the sloping embankment constructed of HPYCS. Uniform spacing of RPP provides sufficient resistance that increases the Factor of Safety (FS) to 1.68 in 2H:1V slopes with deformation of RPP less than 15 mm. The uniform spacing and varied spacing combination of RPP increase the FS to 2.0 with the deformation of RPP less 7 mm.
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Tuncay, Ergün, and Resat Ulusay. "Deterministic and probabilistic treatments of multiplanar pitwall failures at Himmetoglu (Turkey) coal mine." Canadian Geotechnical Journal 38, no. 4 (August 1, 2001): 828–49. http://dx.doi.org/10.1139/t01-015.
Full textAbstract:
This paper describes the investigation of a large and progressive slope failure in the south sidewall of the Himmetoglu coal mine in northwest Turkey. A number of slope instabilities leading to interruptions in mining have been experienced at the mine. Geotechnical investigations consisted of structural mapping, observations of instabilities, review of detailed groundwater information, long-term monitoring of slope movement, and back-analysis of the various failure modes. Deterministic and probabilistic approaches based on the limiting-equilibrium method were employed to examine various slope profiles and excavation sequences for achieving better stability conditions. Analysis of the movement monitoring records and geotechnical information indicated that the failure of the south sidewall slope developed by a combination of sliding along the bedding planes in the hanging wall and faults in the mode of multiplanar sliding. The movement history and the results from the back-analysis of the failures revealed that the stability of the slope was highly sensitive to changes in the length of the lower part of the sliding surface, and the shear strength reduced to residual values along the discontinuity surfaces 8-10 m above the coal seam at the time of failure. The results of the analysis both from deterministic and probabilistic approaches suggest that an excavation sequence consisting of a number of stripping stages from the uppermost benches and advancing to the toe of the slope may provide the resistance to stabilize the overall slope. Simple and preliminary economic assessments based on the overburden costs in conjunction with the deterministic and probabilistic approaches are briefly discussed.Key words: back-analysis, deterministic approach, Himmetoglu coalfield, monitoring, multiplanar failure, probabilistic approach, shear strength, slope stability.
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Dorn, Matthew D. "Effects of Maintenance Human Factors in Maintenance-Related Aircraft Accidents." Transportation Research Record: Journal of the Transportation Research Board 1517, no. 1 (January 1996): 17–28. http://dx.doi.org/10.1177/0361198196151700103.
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To help prevent maintenance-related aircraft accidents the complex factors behind previous accidents must be understood. Maintenance-related aircraft accidents were studied to determine the effects of maintenance human factors. A taxonomy of causal factors was developed and used to classify the causes of 101 military and civilian accidents and to determine the frequency of occurrence for each factor. The taxonomy identifies elements, such as people and hardware, interfaces between elements (i.e., human factors), and maintenance processes comprised of elements and interfaces. Human factors were found to have a significant effect in the 86 military and 15 civilian maintenance-related accidents studied. Whereas investigation boards were found to focus most heavily on element failures, a majority of the failures were found to occur at the process level. Maintenance instructions and their interfaces with the maintainers and inspectors who use them were the most frequently failed elements and interfaces, respectively. Recommendations are made to guide further research, and ideas are provided for improving process analysis by maintenance units and investigation boards.
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Zheng, Hao, Shansuo Zheng, Yixin Zhang, Yonglong Cai, Ming Ming, and Jingliang Zhou. "Experimental Investigation on Seismic Behaviours of Reinforced Concrete Columns under Simulated Acid Rain Environment." Advances in Civil Engineering 2020 (March 25, 2020): 1–15. http://dx.doi.org/10.1155/2020/3826062.
Full textAbstract:
The purpose of this paper was to systematically investigate the influence of acid rain environments on the seismic behaviour of a reinforced concrete (RC) column. Six RC column specimens with shear span ratios of 2.84 were tested under low cyclic reversed loads after being subjected to accelerated corrosion tests in an artificial climate. The corrosion level and stirrup ratio were used as the control variables. The corrosion ratios of the longitudinal rebars ranged from 0 to 13.17%, and the corrosion ratios of the stirrups varied from 0 to 6.75%. The seismic behaviours of the column specimens were analysed with respect to visual damage, failure mode, hysteresis behaviour, load-carrying capacity, deformation capacity, stiffness degradation, and energy dissipation behaviour. The test results showed that the appearance characteristics of the six column specimens exhibited varying degrees of visual damage as a result of the simulated acid rain exposure. All six specimens were dominated by similar flexural-shear failures under low cyclic reversed loads, regardless of the distinctions in the corrosion levels or stirrup ratios. For the specimens with the same ratios of stirrup, as the corrosion level increased, the load-carrying capacity, deformation capacity, stiffness, and energy dissipation capacity were continuously decreased. For the specimens with the same levels of corrosion, the higher the stirrup ratio was, the stronger the restraint effect of the stirrups on the concrete, and the seismic behaviours of the specimens were obviously improved.
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Nguyen, Phu Minh Vuong, Tomasz Olczak, and Sywester Rajwa. "An investigation of longwall failure using 3D numerical modelling – A case study at a copper mine." Studia Geotechnica et Mechanica 43, no. 4 (October 7, 2021): 389–410. http://dx.doi.org/10.2478/sgem-2021-0019.
Full textAbstract:
Abstract It is well-known that the longwall mining method (with roof caving) is widely used in underground mining extraction for bedded deposits (e.g. coal) due to its numerous advantages. Generally, this method is not commonly applied for ore deposits such as copper deposit. In Poland, the longwall mining method has been tested for thin copper deposits at the Polkowice-Sieroszowice copper mine (KGHM). Various failure modes were observed during longwall operation in the 5A/1 panel. This paper aims to examine these occurred failures. To do so, an analysis has been conducted using 3D numerical modelling to investigate the failure mode and mechanism. Based on the 3D numerical modelling results with extensive in situ measurements, causes of failure are determined and practical recommendations for further copper longwall operations are presented.
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Orense, Rolando P., Masayuki Hyodo, Hiroaki Kanda, and Junya Ohashi. "Geotechnical aspects of the 2007 Niigataken Chuetsu-Oki, Japan earthquake." Bulletin of the New Zealand Society for Earthquake Engineering 41, no. 2 (June 30, 2008): 83–89. http://dx.doi.org/10.5459/bnzsee.41.2.83-89.
Full textAbstract:
On 16 July 2007, an earthquake of magnitude 6.8 occurred with an epicentre off the west coast of Niigata Prefecture (Japan), causing widespread damage to buildings and other types of civil engineering structures due to ground shaking and earthquake-induced ground failures. Landsliding and soil liquefaction occurred extensively in various parts of the affected region. This paper presents the preliminary results of the post-earthquake damage investigation conducted at the affected areas after the earthquake, with emphasis on the seismic-induced ground failures and their effects on the built environment.
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Huang, Zhi, Chaochen Ma, and Hong Zhang. "Investigation of Flow Distortion Generated Forced Response of a Radial Turbine with Vaneless Volute." International Journal of Turbo & Jet-Engines 37, no. 2 (September 25, 2020): 141–51. http://dx.doi.org/10.1515/tjj-2017-0016.
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AbstractFor a radial turbine with vaneless volute, the inflow of turbine rotor usually has a circumferential flow distortion due to the influence of the volute tongue. The rotating blades of the rotor are exposed to harmonic aerodynamic loads caused by the distortion, which may induce rotor resonance and lead to high cycle failures (HCF). To understand the forced response mechanism clearly, a numerical analysis was carried out based on a fluid structure interaction (FSI) method. The pressure functions were extracted from the results of a computational fluid dynamics (CFD) analysis by Fourier decomposition. The first three harmonic pressures were identified as the primary engine order (EO) excitations and imposed on the structural model for computational structural dynamics (CSD) simulation. The quantification and assessment of the rotor response were attained by mode superposition method. The simulation results are shown to be consistent with the predictions of Singh’s advanced frequency evaluation (SAFE) diagram.
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Zhou, Han Qiu, and Bo Qin Gu. "Investigation into Leakage Behavior of Bolted Flanged Connection with Octagonal Gasket." Advanced Materials Research 44-46 (June 2008): 165–71. http://dx.doi.org/10.4028/www.scientific.net/amr.44-46.165.
Full textAbstract:
Structural strength and leakage failures are two types of main failures of the bolted flanged connection with octagonal gasket, and they are related to the gasket contact stress and gasket effective contact width to a great extent. The deformation behavior of connection subjected to various bolt loads and medium pressures is studied by numerical simulation. The distribution of the gasket actual contact stress, the change of the gasket average contact stress and gasket effective contact width are discussed. The relationship among the gasket average contact stress, the gasket effective contact width, bolt load and medium pressure are obtained. A model for predicting the leakage rate of the sealing connection with octagonal gasket is developed. Research indicates that the gasket actual contact stress distributes non-uniformly, and at gasket outer flank it is much larger than that at gasket inner flank. Both the gasket average contact stress and the gasket effective contact width increase with increasing bolt load and medium pressure. The leakage rate is largely related to working conditions, gasket contact stress, gasket effective contact area, and so on. The leakage rate decreases with increasing gasket effective contact area and gasket average contact stress, and it increases linearly with increasing medium pressure. The leakage through the octagonal gasket connection shows the characteristic of the laminar flow of incompressible viscous fluid.
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Donati, Davide, Doug Stead, Davide Elmo, and Lisa Borgatti. "A Preliminary Investigation on the Role of Brittle Fracture in the Kinematics of the 2014 San Leo Landslide." Geosciences 9, no. 6 (June 7, 2019): 256. http://dx.doi.org/10.3390/geosciences9060256.
Full textAbstract:
The stability of high rock slopes is largely controlled by the location and orientation of geological features, such as faults, folds, joints, and bedding planes, which can induce structurally controlled slope instability. Under certain conditions, slope kinematics may vary with time, as propagation of existing fractures due to brittle failure may allow development of fully persistent release surfaces. In this paper, the progressive accumulation of brittle damage that occurred prior to and during the 2014 San Leo landslide (northern Italy) is investigated using a synthetic rock mass (SRM) approach. Mapping of brittle fractures, rock bridge failures, and major structures is undertaken using terrestrial laser scanning, photogrammetry, and high-resolution photography. Numerical analyses are conducted to investigate the role of intact rock fracturing on the evolution of kinematic freedom using the two-dimensional Finite-discrete element method (FDEM) code Elfen, and the three-dimensional lattice-spring scheme code Slope Model. Numerical analyses show that the gradual erosion of clay-rich material below the base of the plateau drives the brittle propagation of fractures within the rock mass, until a fully persistent, subvertical rupture surface form, causing toppling of fault-bounded rock columns. This study clearly highlights the potential role of intact rock fracturing on the slope kinematics, and the interaction between intact rock strength, structural geology, and slope morphology.
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Udovič, Dalibor, Branko Kordić, and Željko Arbanas. "Geotechnical Study of Raspadalica Cliff Rockfall, Croatia." Applied Sciences 12, no. 13 (June 28, 2022): 6532. http://dx.doi.org/10.3390/app12136532.
Full textAbstract:
The Raspadalica Cliff is an almost vertical 100 m high limestone cliff with a railway line at its foot and is known for numerous rockfall occurrences in the past. This article presents the results of the geotechnical study of the cliff based on a traditional geological and geotechnical field survey and remote sensing analysis. Both the traditional geological and geotechnical field survey and remote sensing surveys and analyses enabled the establishment of the structural model of the Raspadalica Cliff and the determination of the discontinuity sets and discontinuity features, such as orientation, spacing, persistence, roughness, discontinuity wall strength, aperture, degree of weathering of discontinuity wall, seepage conditions, and the presence and hardness of discontinuity filling. Kinematic analyses were performed on five cliff zones with slightly different structural features, indicating a relatively low probability of typical failures in the cliff rock mass that precede the rockfall occurrences. Although rockfall phenomena from the cliff face are relatively frequent, the kinematic analyses did not indicate a high probability of their occurrence. The aim of this manuscript is to make scientists and practitioners aware that investigation of rock mass cliffs and possible rockfall failures must not be based on usual methods without critical review of the obtained results and consequences. The combined use of traditional geological and geotechnical methods and more commonly used advanced remote sensing methods leads to better modelling, while the analysis of more associated failure modes can explain the triggering of rockfall.
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Shischenko, Elena, Anton Alekseev, and Vera Novikova. "COMPOSITIONAL MODEL DEVELOPMENT OF DC DRIVE MOTOR RELIABILITY ESTIMATE FOR TRAM-CARS." Bulletin of Bryansk state technical university 2020, no. 8 (August 2, 2020): 39–46. http://dx.doi.org/10.30987/1999-8775-2020-8-39-46.
Full textAbstract:
The investigation purpose is to develop a method for the assessment of reliability values of dc drive motors for tram cars the life of which approaches its completion which will allow correcting the maintenance and repair system in order to decrease the number of sudden failures and hence the number of unscheduled repair operations. According to the available rolling-stock (trams) repair statistics, a considerable part of unscheduled repair works is determined by failures of dc drive motors.
Reasoning from the investigation purpose one of the problems consists in the development of the simulator allowing the accurate definition of quantitative characteristics of reliability during the operation. The operation reliability of dc drive motors of tram-cars is affected considerably by the interaction of design structure elements and it raises a question of combined structural-functional patterns use during the formation of a compositional simulator for reliability estimate.
The results obtained show that the account of structural-functional ties of dc drive motors design elements in tram-cars during the simulator formation for reliability assessment allows obtaining more correct data for the definition of maintenance terms and repair works.
In such a way, the compositional model for reliability assessment of dc drive motors installed in tram-cars allows obtaining more exact dependences of their trouble-free operation probability that gives an opportunity to correct terms for scheduled-preventive repair, so that to decrease the number of sudden failures becoming more often, as it is seen in practice, at the approach of tram-car operation completion and decrease the number of unscheduled repair works.
The model offered for reliability assessment is urgent for the term correction of maintenance and repair works of tram-car dc drive motors the life of which comes to the completion and also for motors which run out of power.
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Bouatia, Mohammed, Rafik Demagh, and Zohra Derriche. "Numerical Investigation on Buried Pipelines Subjected to Permanent Ground Deformations Due to Shallow Slope Failure." Jordan Journal of Civil Engineering 17, no. 1 (January 1, 2023): 71–82. http://dx.doi.org/10.14525/jjce.v17i1.07.
Full textAbstract:
Permanent ground deformations (PGDs) induced by slope failures cause catastrophic damage to buried pipelines. This paper presents a 2D plane-strain numerical analysis of the behavior of a 800 mm water transport pipeline buried in the Aine-Tine slope (Mila, Algeria) subjected to shallow PGD, as it could be triggered by the recent earthquake of August 07th, 2020 (M= 4.9). The analysis is carried out through the application of an incremental displacement to simulate the soil-pipeline interaction while focusing on the effect of (1) the magnitude of the PGD and (2) the rigidity of the pipeline on the structural response of the pipeline. The elasticperfectly Mohr-Coulomb model was used to simulate the soil behavior and the elastic model was used to simulate that of the steel pipe. Pipeline deformations (i.e., translation and ovalization) and radial internal forces’ (i.e., axial forces F, shear forces Fୗ and bending moments M) results highlighted that shallow PGD can exert additional loads on pipelines that are proportional to the magnitude of the PGD. It has been found that the soil deformations as well as the internal forces induced on the pipeline ring are higher for rigid pipelines. Moreover, the results indicated that rigid pipelines are more effective than flexible ones as far as ovalization-serviceability limit state is concerned. In effect, for PGD magnitudes of 0.5, 1 and 2 m, the ovalization values of the flexible pipeline are, respectively, higher by 23%, 21% and 18% than those calculated for the rigid pipeline. Through a simplified linear numerical simulation such as that presented in this study, engineers and planners could be guided to foresee the possible causes of pipeline leaks and the mechanisms of ruptures that lead very often to severe disruption of pipelines’ normal operation. KEYWORDS: Soil-structure interaction, Slope failure, Permanent ground deformation, Pipelines, Radial internal forces, Ovalization
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Wetterling, Friedrich, Kenneth Hun Mok, Ciaran McGoldrick, and Biswajit Basu. "Non-Destructive Investigation of Glass Fiber Reinforced Composites via Magnetic Resonance Imaging." Key Engineering Materials 569-570 (July 2013): 126–31. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.126.
Full textAbstract:
Glass fibre reinforced composites (GFRC), used in the manufacture of wind turbine blades, can suffer unpredictable, post-manufacturing, in-situ structural failure. The economic cost of remediation of such blade failures is extremely high, both on land and offshore. We suggest using zero-time-to-echo (ZTE) magnetic resonance imaging (MRI) as a method for characterising glass fibre reinforced composites. Initially, we demonstrate that carbon-13 Nuclear Magnetic Resonance (NMR) spectra acquired at 800MHz provide finger-print like information and that there is sufficient hydrogen-1 NMR signal available to conduct MRI. This work explores the efficacy of using zero timetoecho (ZTE) magnetic resonance imaging (MRI) to detect the rapidly decaying Hydrogen-1 (1H) NMR signal from a representative sample. A 400MHz surface resonator was developed made of a 20mm diameter loop formed with 1.5mm thick silver wire and designed with variable tuning and matching in order to investigate the 1H-MRI signal at 9.4T static magnetic field strength. The thickness of the GFRC was determined from the MRI data to be 3.51±0.28mm while the physical measurement using a caliper device resulted in a measurement of 3.45mm. Hence, a high spatial resolution accuracy is provided by ZTE MRI. Very short T2* (<20μs) of the material led to stronger blurring artefacts for the blade material compared to heat shrink used for insulating the silver wire of the detector. 1H images of the blade material were acquired demonstrating that ZTE is a suitable technique for acquiring image data from glass fibre materials. Work is on-going in studying the relaxation time parameters and chemical frequency shifts for materials with and without structural weaknesses in order to improve the predictive power of the technique. In conclusion, ZTE-MRI can provide useful information about the mechanical properties of glass fibre reinforced composites.
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Kaltakci, Mevlut Yasar, Hasan Husnu Korkmaz, Mehmet Kamanli, Murat Ozturk, and Musa Hakan Arslan. "Evaluation of a Gravity Load Designed Reinforced Concrete Structure Failed under its Own Weight due to Creep in Concrete." Advanced Materials Research 747 (August 2013): 441–44. http://dx.doi.org/10.4028/www.scientific.net/amr.747.441.
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Turkish building stock is commonly composed of reinforced concrete moment resisting frames. Recent earthquakes in Turkey resulted thousands of failed or heavily damaged residential houses and office buildings. In addition of the earthquake failures, reinforced concrete structures may also failed only under their own weight. There are several examples such as Hicret Apartment in Diyarbakir (1983), Zumrut Apartment in Konya, in central Anatolia, Huzur Apartment in Istanbul (2007). On February 2nd, 2004 a 9-story reinforced concrete building in Konya (Zumrut Apartment) collapsed leaving 92 people dead. The first author of the paper was governmentally charged about the investigation of the failure causes. Carrot samples were taken from the concrete columns and steel samples were obtained from the disaster area. The dimensions of the structural members were determined. The structure was modeled in three dimensional space and vertical collapse analyses were conducted. The one of the main cause of failure was determined as the creep of the concrete occurred in excessively loaded columns. The main reasons of the damages and failures were determined to be the insufficiency in material quality, mistakes made in load selection and the inappropriate load-carrying dimensions. The construction mistakes and not obeying the design drawings are the other flaws. In this paper detailed information about the structure, creep analyses and vertical collapse analyze results were depicted in understandable format.
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Roy, S., and J. N. Reddy. "Nonlinear Viscoelastic Finite Element Analysis of Adhesive Joints." Tire Science and Technology 16, no. 3 (July 1, 1988): 146–70. http://dx.doi.org/10.2346/1.2148803.
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Abstract A good understanding of the process of adhesion from the mechanics viewpoint and the predictive capability for structural failures associated with adhesively bonded joints require a realistic modeling (both constitutive and kinematic) of the constituent materials. The present investigation deals with the development of an Updated Lagrangian formulation and the associated finite element analysis of adhesively bonded joints. The formulation accounts for the geometric nonlinearity of the adherends and the nonlinear viscoelastic behavior of the adhesive. Sample numerical problems are presented to show the stress and strain distributions in bonded joints.
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Danial, Syed Nasir, Doug Smith, and Brian Veitch. "A Method to Detect Anomalies in Complex Socio-Technical Operations Using Structural Similarity." Journal of Marine Science and Engineering 9, no. 2 (February 18, 2021): 212. http://dx.doi.org/10.3390/jmse9020212.
Full textAbstract:
Traditional techniques for accident investigation have hindsight biases. Specifically, they isolate the process of the accident event and trace backward from the event to determine the factors leading to the accident. Nonetheless, the importance of the contributing factors towards a successful operation is not considered in conventional accident modeling. The Safety-II approach promotes an examination of successful operations as well as failures. The rationale is that there is an opportunity to learn from successful operations, in addition to failure, and there is an opportunity to further differentiate failure processes from successful operations. The functional resonance analysis method (FRAM) has the capacity to monitor the functionality and performance of a complex socio-technical system. The method can model many possible ways a system could function, then captures the specifics of the functionality of individual operational events in functional signatures. However, the method does not support quantitative analysis of the functional signatures, which may demonstrate similarities as well as differences among each other. This paper proposes a method to detect anomalies in operations using functional signatures. The present work proposes how FRAM data models can be converted to graphs and how such graphs can be used to estimate anomalies in the data. The proposed approach is applied to human performance data obtained from ice-management tasks performed by a cohort of cadets and experienced seafarers in a ship simulator. The results show that functional differences can be captured by the proposed approach even though the differences were undetected by usual statistical measures.
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Adasooriya, Nirosha D., Tor Hemmingsen, and Dimitrios Pavlou. "Environment-assisted corrosion damage of steel bridges: a conceptual framework for structural integrity." Corrosion Reviews 38, no. 1 (February 25, 2020): 49–65. http://dx.doi.org/10.1515/corrrev-2019-0066.
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AbstractA framework is presented in this paper to assess the structural integrity of steel bridges for environment-assisted corrosion damage. Forms of corrosion of steel bridges and their effects, possible locations of occurrence, and most appropriate inspection techniques are first studied and the lessons learned from past steel bridge failures are discussed. A review of the corrosion damage of steel bridges, including causes, effects, and control measures, is presented along with guidelines for the recognition and investigation of environment-assisted cracking (EAC) of steel bridges. Experimental approaches are proposed to investigate the EAC of structural steel. The proposed approach is used to investigate the EAC susceptibility of cathodically protected ST52 steel. In addition, the feasibility of the proposed approach is tested. Hence, the conceptual framework is proposed. The framework aims to support the inspection and maintenance practices of steel bridges.
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Naghshineh, Bardia, and Maryam Lotfi. "Enhancing supply chain resilience: an empirical investigation." Continuity & Resilience Review 1, no. 1 (August 29, 2019): 47–62. http://dx.doi.org/10.1108/crr-09-2018-0002.
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PurposeSupply chain resilience (SCR) has recently become an important issue for organizations all around the world. In order to decrease the risk of failures, managers and decision makers are constantly looking for practices to enhance SCR. The purpose of this paper is to propose a research model that mainly focuses on the effect of information sharing (IS) to enhance SCR.Design/methodology/approachSurvey method is used in this research. Data were collected from the supply chain, procurement, executive and IT managers of 82 of Tehran’s stock exchange production companies. Structural equation modeling with SmartPLS3 software is used to analyze the collected data.FindingsResearch results show that IS significantly enhances SCR.Research limitations/implicationsData were collected at one point in time, and therefore a longitudinal study can further investigate the results of this study. The research was carried out in production companies in Iran. Future research can examine the research model in other industry sectors, e.g. services, in other countries to validate the accuracy of the findings.Practical implicationsThe findings of this research should help managers, and decision makers create more resilient supply chains for their own and partners’ organizations.Originality/valueThe research model provides insightful results regarding the significance of IS in the SCR context.
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Chen, Xiangxiang, Xudong Chen, Andrew Chan, Yingyao Cheng, and Hongfan Wang. "A FDEM Parametric Investigation on the Impact Fracture of Monolithic Glass." Buildings 12, no. 3 (February 25, 2022): 271. http://dx.doi.org/10.3390/buildings12030271.
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Due to the brittleness, monolithic glass may fracture under impact, resulting in catastrophic sequences. The combined finite-discrete element method, i.e., FDEM, is employed to investigate both the oblique and the perpendicular impact failures of monolithic glass parametrically, particularly the soda-lime glass. Using FDEM, glass is discretised into discrete elements where a finite element formulation is incorporated, leading to accurate evaluation of the contact forces and structural deformation. Following the basic theories of the FDEM, a cohesive Mode I fracture model of glass is briefly introduced. Numerical examples are given for the verification of the employed fracture model and the applicability of the FDEM, and comparisons have been made against the computational and experimental results in the literature. The investigated parameters include the impact velocity, the impact angle, the material properties of glass, etc. The obtained results not only revealed the impact fracture mechanism of soda-lime glass but also provided guidance for its design and manufacturing.
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di Carlo, Fabio, Simona Coccia, and Mario Como. "Rocking in Presence of Cracking of Masonry Wall Piers." Key Engineering Materials 747 (July 2017): 678–85. http://dx.doi.org/10.4028/www.scientific.net/kem.747.678.
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The wall pier represents the vertical element of multi-storey walls with openings, the main resistant structural components of a masonry building. Structural systems of wall piers and spandrels are required to sustain the in-plane seismic actions acting on the wall, opposing with their weights to the action of horizontal forces. The behavior of masonry constructions results to be very far from the one characterizing ductile structures, because of the lack of energy dissipation during the deformation. A strength resource of masonry structures, properly reinforced in order to avoid early local failures, consists in exhibiting rocking behavior, until a failure condition is attained. An investigation on the dynamic behavior of masonry wall piers is carried out by following Housner’s studies and properly introducing the effect of diagonal cracks, shown by typical post-earthquake cracking patterns. As a consequence, the system is characterized by the detachment of a lower triangular region that becomes ineffective during the development of the mechanism and does not oppose with its weight to the overturning. Finally, it is shown that the occurrence of diagonal cracks can be prevented by the execution of suitable retrofit interventions.
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Klimeš, J., I. Baroň, T. Pánek, T. Kosačík, J. Burda, F. Kresta, and J. Hradecký. "Investigation of recent catastrophic landslides in the flysch belt of Outer Western Carpathians (Czech Republic): progress towards better hazard assessment." Natural Hazards and Earth System Sciences 9, no. 1 (February 13, 2009): 119–28. http://dx.doi.org/10.5194/nhess-9-119-2009.
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Abstract. Rapid snow melting and intense precipitation triggered and reactivated tens of mostly shallow landslides in the eastern part of the Czech Republic at the turn of March and April 2006. This area is build up by highly fractured flysch rock units with variable content of sandstones and claystones. The landslide complex at Hluboče (Brumov-Bylnice town) is composed of shallow translational (up to 10 m thick) as well as deep-seated (up to 20 m thick) rotational landslides, which generated a catastrophic earthflow at their toe. This earthflow destroyed three buildings, the access road and caused total loss of about 350 000 EUR. Detailed field investigation, review of the archive sources and interviewing of local inhabitants allowed brief description of slope movement history prior the catastrophic event as well as detailed reconstruction of slope failure mechanisms during the main movement activity (3–4 April 2006). This information, along with the detailed description of the passive as well as active causative factors (structural and morphologic settings) can contribute towards better identification of potentially dangerous slope failures in the study region.