Journal articles: 'Collapse model'

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Mohamadi, Bahaa, Timo Balz, and Ali Younes. "Towards a PS-InSAR Based Prediction Model for Building Collapse: Spatiotemporal Patterns of Vertical Surface Motion in Collapsed Building Areas—Case Study of Alexandria, Egypt." Remote Sensing 12, no. 20 (October 12, 2020): 3307. http://dx.doi.org/10.3390/rs12203307.

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Buildings are vulnerable to collapse incidents. We adopt a workflow to detect unusual vertical surface motions before building collapses based on PS-InSAR time series analysis and spatiotemporal data mining techniques. Sentinel-1 ascending and descending data are integrated to decompose vertical deformation in the city of Alexandria, Egypt. Collapsed building data were collected from official sources, and overlayed on PS-InSAR vertical deformation results. Time series deformation residuals are used to create a space–time cube in the ArcGIS software environment and analyzed by emerging hot spot analysis to extract spatiotemporal patterns for vertical deformation around collapsed buildings. Our results show two spatiotemporal patterns of new cold spot or new hot spot before the incidents in 66 out of 68 collapsed buildings between May 2015 and December 2018. The method was validated in detail on four collapsed buildings between January and May 2019, proving the applicability of this workflow to create a temporal vulnerability map for building collapse monitoring. This study is a step forward to create a PS-InSAR based model for building collapse prediction in the city.

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Tan, Fei, Wufeiyu Tan, Feifei Yan, Xin Qi, Qinghua Li, and Zhikai Hong. "Model Test Analysis of Subsurface Cavity and Ground Collapse Due to Broken Pipe Leakage." Applied Sciences 12, no. 24 (December 19, 2022): 13017. http://dx.doi.org/10.3390/app122413017.

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Urban ground collapse is a common geological disaster characterized by its invisible nature, particularly in China, and results in significant socioeconomic losses and even loss of life. Underground pipeline breakage is the most common factor leading to urban ground collapses. Hence, it is essential to study how different types of pipeline breakages initiate the collapse mechanism. In this study, an indoor model test was conducted to directly observe the process of collapse due to broken pipe leakage. A broken pipe was put into a model box and tested by an experimental device. The results showed that among the different pipeline breakage types, vertical damage had the greatest influence on the degree of cavity development and ground collapse. Similarities were observed in the patterns of cavity evolution development and the extent of ground collapse as well, further revealing the significance of the cavity evolution process in predicting ground collapses.

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Kella, Offer, and Andreas Löpker. "A MARKOV-MODULATED GROWTH COLLAPSE MODEL." Probability in the Engineering and Informational Sciences 24, no. 1 (December 21, 2009): 99–107. http://dx.doi.org/10.1017/s0269964809990155.

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We consider a growth collapse model in a random environment for which the input rates might depend on the state of an underlying irreducible Markov chain and at state change epochs there is a possible downward jump to a level that is a random fraction of the level just before the jump. The distributions of these jumps are allowed to depend on both the originating and target states. Under a very weak assumption we develop an explicit formula for the conditional moments (of all orders) of the time stationary distribution. We then consider special cases and show how to use this result to study a growth collapse process in which the times between collapses have a phase-type distribution.

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Thorson, James T., Trevor A. Branch, and Olaf P. Jensen. "Using model-based inference to evaluate global fisheries status from landings, location, and life history data." Canadian Journal of Fisheries and Aquatic Sciences 69, no. 4 (April 2012): 645–55. http://dx.doi.org/10.1139/f2012-016.

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Assessing fishery collapses worldwide is hindered by the lack of biomass data for most stocks, leading to the use of landings-based proxies or the assumption that existing stock assessments are globally representative. We argue that the use of sparse assessments to evaluate fishery status requires model-based inference because assessment availability varies spatially and temporally, and we derive a model that extrapolates from assessment results to available landings, life history, and location data. This model uses logistic regression to classify stocks into different prediction bins and estimates the probability of collapse in each using cross-validation. Results show that landings, life history, and location are informative to discriminate among different probabilities of collapse. We find little evidence that regions with fewer assessments have a greater proportion of collapsed stocks, while acknowledging weak inferential support regarding regions with one or fewer assessments. Our extrapolation suggests that 4.5%–6.5% of stocks defined by landings data are collapsed, but that this proportion is increasing. Finally, we propose a research agenda that combines stock assessment and landings databases while overcoming limitations in each.

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Wang, Yi Xuan, and Lei Huang. "Research on Numerical Model for Earthquake Induced Progressive Collapse of High-Rise Buildings." Applied Mechanics and Materials 716-717 (December 2014): 223–26. http://dx.doi.org/10.4028/www.scientific.net/amm.716-717.223.

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Progressive collapse is defined as the collapse of the whole building due to local weak stories or weak zones. In this paper, collapse should theoretically be avoided for any building under any earthquake, it is necessary to study the collapse behavior of buildings to acquire a better understanding of the collapse mechanism and to find efficient methods to prevent it. The collapse process highly depends on the feature of the whole structural system, so numerical simulation becomes a major method to study it. Based on the finite element method, by selecting the appropriate cell death and cell contact algorithm criterion can better simulate the structure collapsed in an earthquake under the continuity of the whole process of destruction, to help understand the causes and mechanism of structural damage. The real buildings are analyzed to study the failure mechanism of the structure. The models proposed are reasonable to study the seismic collapse mechanism of high-rise buildings.

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DEL POPOLO, ANTONINO. "IMPROVEMENTS TO THE SPHERICAL COLLAPSE MODEL." International Journal of Modern Physics D 15, no. 07 (July 2006): 1067–88. http://dx.doi.org/10.1142/s0218271806008553.

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We study the joint effect of dynamical friction, tidal torques and cosmological constant on clusters of galaxy formation. We show that within high-density environments, such as rich clusters of galaxies, both dynamical friction and tidal torques slow down the collapse of low-ν peaks producing an observable variation in the time of collapse of the perturbation and, as a consequence, a reduction in the mass bound to the collapsed perturbation. Moreover, the delay of the collapse produces a tendency for less dense regions to accrete less mass, with respect to a classical spherical model, inducing a biasing of over-dense regions toward higher mass. We show how the threshold of collapse is modified if dynamical friction, tidal torques and a non-zero cosmological constant are taken into account and we use the Extended Press–Schecter (EPS) approach to calculate the effects on the mass function. Then, we compare the numerical mass function given in D. Reed, Mon. Not. R. Astron. Soc.346, 565 (2003) with the theoretical mass function obtained in the present paper. We show that the barrier obtained in the present paper gives rise to a better description of the mass function evolution with respect to other previous models, R. K. Sheth and G. Tormen, Mon. Not. R. Astron. Soc.308, 119 (1999) and R. K. Sheth and G. Tormen, Mon. Not. R. Astron. Soc.329, 61 (2002).

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Xu, Qinghu, Xuezhi Zhen, Yu Zhang, Mengjun Han, and Wenkang Zhang. "Numerical Simulation Study of Progressive Collapse of Reinforced Concrete Frames with Masonry Infill Walls under Blast Loading." Modelling and Simulation in Engineering 2022 (November 11, 2022): 1–16. http://dx.doi.org/10.1155/2022/1781415.

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The influence of masonry infill walls on the progressive collapse performance of reinforced concrete (RC) frame structures was investigated in this paper, using a nonlinear dynamic analysis approach. Based on ANSYS/LS-DYNA finite element software, two finite element models of RC frame structures with and without masonry infilled walls were established. Then, the collapse modes of the two RC frame structure models were analyzed for different scaled distance blast loads, different locations of column damage, and different span numbers. The results show that with the increase of explosive amount, the collapse degree of the structure is more serious in the same time. Under the condition of destroying the outermost central column, the degree of progressive collapse of the RC frame model with infilled walls in the same time is lower than that of the RC frame model without infilled walls. The RC frame model with infilled walls is more resistant to collapse when the outermost side columns are damaged. With the increase of span number, the structure is more likely to be damaged and collapsed.

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Xie, Kai Zhong, Guang Qiang Chen, and Li Lin Wei. "A Damage Model for Collapse-Mechanism of Long-Span and High-Pier Continuous Rigid Frame Bridges." Advanced Materials Research 219-220 (March 2011): 1431–35. http://dx.doi.org/10.4028/www.scientific.net/amr.219-220.1431.

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Collapse-mechanism analysis can simulate that bridges enter strong elasto-plastic and large displacement response and collapses phase, so that it is very important for the seismic design of bridges. In this paper, a damage model of reinforced concrete is introduced, and dynamic response and collapse of long span and high-pier continuous rigid frame bridge during strong earthquake is studied with damage model of reinforced concrete by the explicit dynamic analysis code (LS-DYNA). The simulation results indicate the development of the concrete elements from cracking to failure and the bridge from part collapse to the whole collapse of the bridge are studied. The damage and collapse mechanisms during strong earthquake are given of Long Span and High-pier Continuous Rigid Frame Bridges. References are provided for seismic analysis of this kind of bridges.

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Akbari, Amir, Reghan J. Hill, and Theo G. M. van de Ven. "An elastocapillary model of wood-fibre collapse." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, no. 2179 (July 2015): 20150184. http://dx.doi.org/10.1098/rspa.2015.0184.

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An elastocapillary model for drying-induced collapse is proposed. We consider a circular elastic membrane with a hole at the centre that is deformed by the capillary pressure of simply and doubly connected menisci. The membrane overlays a cylindrical cavity with rigid walls, trapping a prescribed volume of water. This geometry may be suitable for studying structural failures and stiction in micro-electromechanical systems during wet etching, where capillary surfaces experience catastrophic transitions. The dry state is determined using the dihedral-angle and volume-turning-point stability criteria. Open and collapsed conformations are predicted from the scaled hole radius, cavity aspect ratio, meniscus contact angle with the membrane and cavity walls, and an elastocapillary number measuring the membrane stretching rigidity relative to the water surface tension. For a given scaled hole radius and cavity aspect ratio, there is a critical elastocapillary number above which the system does not collapse upon drying. The critical elastocapillary number is weakly influenced by the contact angle over a wide range of the scaled hole radius, thus indicating a limitation of surface hydrophobization for controlling the dry-state conformation. The model is applied to the drying of wood fibres above the fibre saturation point, determining the conditions leading to collapse.

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Huang, Sheng Nan, Xin Zheng Lu, and Lie Ping Ye. "A Hysteretic Model of Conventional Steel Braces and an Analysis of the Collapse Prevention Effect of Brace Strengthening." Applied Mechanics and Materials 174-177 (May 2012): 3–10. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.3.

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A hysteretic model of conventional steel braces consisting of 18 parameters is proposed. This model is able to simulate the hysteretic behavior of conventional steel braces accurately. The collapse-prevention strengthening effect with steel braces for a typical reinforced concrete (RC) frame that was close to the epicenter and collapsed during the Great Wenchuan Earthquake is discussed via push-over analysis and collapse fragility analysis based on incremental dynamic analysis. The result could be referred to for the seismic collapse prevention design of RC frames.

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Cheng, X. S., G. Zheng, Y. Diao, T. M. Huang, C. H. Deng, D. Q. Nie, and Y. W. Lei. "Experimental study of the progressive collapse mechanism of excavations retained by cantilever piles." Canadian Geotechnical Journal 54, no. 4 (April 2017): 574–87. http://dx.doi.org/10.1139/cgj-2016-0284.

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An increasing number of catastrophic progressive collapses of deep excavations have occurred throughout the world. However, the research on progressive collapse mechanisms is limited. In this paper, two categories of model tests were conducted to investigate the mechanism of partial collapse (sudden failures of certain retaining piles) and progressive collapse. The model test results show that partial collapse can cause a sudden increase in the bending moments of adjacent piles via an arching effect. The load-transfer coefficients are defined to be equal to the peak increase ratios of the maximum bending moments in adjacent piles (peak moments caused by collapse over the values before the collapse). When the maximum load-transfer coefficient is larger than the bearing capacity safety factor of the piles, the partial failure will lead to progressive collapse. The influential factors of the progressive collapse mechanism, such as the partial collapse extent, excavation depth, and capping beam, were also investigated. During progressive collapse, the previous failed pile could cause new stress arching; simultaneously, the soil behind certain nearest intact piles could become loosened and destroy the arch springing of the stress arching, causing the progressive collapse to cease gradually.

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Laffin, Matthew K., Charles S. Zender, Melchior van Wessem, and Sebastián Marinsek. "The role of föhn winds in eastern Antarctic Peninsula rapid ice shelf collapse." Cryosphere 16, no. 4 (April 13, 2022): 1369–81. http://dx.doi.org/10.5194/tc-16-1369-2022.

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Abstract. Ice shelf collapse reduces buttressing and enables grounded glaciers to contribute more rapidly to sea-level rise in a warming climate. The abrupt collapses of the Larsen A (1995) and B (2002) ice shelves on the Antarctic Peninsula (AP) occurred, at least for Larsen B, when long-period ocean swells damaged the calving front and the ice shelf was inundated with melt lakes that led to large-scale hydrofracture cascades. During collapse, field and satellite observations indicate föhn winds were present on both ice shelves. Here we use a regional climate model and machine learning analyses to evaluate the contributory roles of föhn winds and associated melt events prior to and during the collapses for ice shelves on the AP. Föhn winds caused about 25 % ± 3 % of the total annual melt in just 9 d on Larsen A prior to and during collapse and were present during the Larsen B collapse, which helped form extensive melt lakes. At the same time, the off-coast wind direction created by föhn winds helped melt and physically push sea ice away from the ice shelf calving fronts that allowed long-period ocean swells to reach and damage the front, which has been theorized to have ultimately triggered collapse. Collapsed ice shelves experienced enhanced surface melt driven by föhn winds over a large spatial extent and near the calving front, whereas SCAR inlet and the Larsen C ice shelves are affected less by föhn-wind-induced melt and do not experience large-scale melt ponds. These results suggest SCAR inlet and the Larsen C ice shelves may be less likely to experience rapid collapse due to föhn-driven melt so long as surface temperatures and föhn occurrence remain within historical bounds.

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Deng, Kuanhai, Yuanhua Lin, Hu Qiang, Dezhi Zeng, Yongxing Sun, and Lin Xinxin. "New high collapse model to calculate collapse strength for casing." Engineering Failure Analysis 58 (December 2015): 295–306. http://dx.doi.org/10.1016/j.engfailanal.2015.08.036.

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Pavlík, Václav, and Ladislav Šubr. "The hunt for self-similar core collapse." Astronomy & Astrophysics 620 (December 2018): A70. http://dx.doi.org/10.1051/0004-6361/201833854.

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Context. Core collapse is a prominent evolutionary stage of self-gravitating systems. In an idealised collisionless approximation, the region around the cluster core evolves in a self-similar way prior to the core collapse. Thus, its radial density profile outside the core can be described by a power law, ρ ∝ r−α. Aims. We aim to find the characteristics of core collapse in N-body models. In such systems, a complete collapse is prevented by transferring the binding energy of the cluster to binary stars. The contraction is, therefore, more difficult to identify. Methods. We developed a method that identifies the core collapse in N-body models of star clusters based on the assumption of their homologous evolution. Results. We analysed different models (equal- and multi-mass), most of which exhibit patterns of homologous evolution, yet with significantly different values of α : the equal-mass models have α ≈ 2.3, which agrees with theoretical expectations, the multi-mass models have α ≈ 1.5 (yet with larger uncertainty). Furthermore, most models usually show sequences of separated homologous collapses with similar properties. Finally, we investigated a correlation between the time of core collapse and the time of formation of the first hard binary star. The binding energy of such a binary usually depends on the depth of the collapse in which it forms, for example from 100 kT to 104 kT in the smallest equal-mass to the largest multi-mass model, respectively. However, not all major hardenings of binaries happened during the core collapse. In the multi-mass models, we see large transfers of binding energy of ∼104 kT to binaries that occur on the crossing timescale and outside of the periods of the homologous collapses.

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Boxma, Onno, David Perry, Wolfgang Stadje, and Shelemyahu Zacks. "A Markovian growth-collapse model." Advances in Applied Probability 38, no. 1 (March 2006): 221–43. http://dx.doi.org/10.1239/aap/1143936148.

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We consider growth-collapse processes (GCPs) that grow linearly between random partial collapse times, at which they jump down according to some distribution depending on their current level. The jump occurrences are governed by a state-dependent rate function r(x). We deal with the stationary distribution of such a GCP, (Xt)t≥0, and the distributions of the hitting times Ta = inf{t ≥ 0 : Xt = a}, a > 0. After presenting the general theory of these GCPs, several important special cases are studied. We also take a brief look at the Markov-modulated case. In particular, we present a method of computing the distribution of min[Ta, σ] in this case (where σ is the time of the first jump), and apply it to determine the long-run average cost of running a certain Markov-modulated disaster-ridden system.

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Boxma, Onno, David Perry, Wolfgang Stadje, and Shelemyahu Zacks. "A Markovian growth-collapse model." Advances in Applied Probability 38, no. 01 (March 2006): 221–43. http://dx.doi.org/10.1017/s0001867800000884.

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We consider growth-collapse processes (GCPs) that grow linearly between random partial collapse times, at which they jump down according to some distribution depending on their current level. The jump occurrences are governed by a state-dependent rate functionr(x). We deal with the stationary distribution of such a GCP, (Xt)t≥0, and the distributions of the hitting timesTa= inf{t≥ 0 :Xt=a},a> 0. After presenting the general theory of these GCPs, several important special cases are studied. We also take a brief look at the Markov-modulated case. In particular, we present a method of computing the distribution of min[Ta, σ] in this case (where σ is the time of the first jump), and apply it to determine the long-run average cost of running a certain Markov-modulated disaster-ridden system.

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Yu-An, Liu. "Will the Scandinavian model collapse?" Futures 28, no. 5 (June 1996): 471–90. http://dx.doi.org/10.1016/0016-3287(96)00020-1.

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Olsen, Anna H., Thomas H. Heaton, and John F. Hall. "Characterizing Ground Motions that Collapse Steel Special Moment-Resisting Frames or Make Them Unrepairable." Earthquake Spectra 31, no. 2 (May 2015): 813–40. http://dx.doi.org/10.1193/102612eqs318m.

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This work applies 64,765 simulated seismic ground motions to four models each of 6- or 20-story, steel special moment-resisting frame buildings. We consider two vector intensity measures and categorize the building response as “collapsed,” “unrepairable,” or “repairable.” We then propose regression models to predict the building responses from the intensity measures. The best models for “collapse” or “unrepairable” use peak ground displacement and velocity as intensity measures, and the best models predicting peak interstory drift ratio, given that the frame model is “repairable,” use spectral acceleration and epsilon ( ∊) as intensity measures. The more flexible frame is always more likely than the stiffer frame to “collapse” or be “unrepairable.” A frame with fracture-prone welds is substantially more susceptible to “collapse” or “unrepairable” damage than the equivalent frame with sound welds. The 20-story frames with fracture-prone welds are more vulnerable to P-delta instability and have a much higher probability of collapse than do any of the 6-story frames.

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Munro, Angus I. S., and Larry K. Forbes. "Including ionisation in a simple model of single-bubble sonoluminescence." ANZIAM Journal 47, no. 3 (January 2006): 333–58. http://dx.doi.org/10.1017/s1446181100009871.

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AbstractA small gas bubble in a liquid, when driven by intense ultrasound, collapses and emits light in a process called Single-Bubble Sonoluminescence (SBSL). While the dynamics of driven bubbles are well studied, less is known of the physical conditions in the gas or whether it is necessary to include ionisation in simpler studies of bubble dynamics. In this study, a model was derived from Rayleigh-Plesset dynamics, a van der Waals equation of state and the first law of thermodynamics (including interfacial heat transfer and ionisation). Stronger model ionisation reduced the maximum collapse temperature, and altered other collapse characteristics. Chaotic parameter regions are proximal to, but not coincident with, known stable SL regions. Resonant behaviour was only markedly affected by ionisation close to these chaotic regions.

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Piccirilli, María Pía, Gabriel León, Susana J. Landau, Micol Benetti, and Daniel Sudarsky. "Constraining quantum collapse inflationary models with current data: The semiclassical approach." International Journal of Modern Physics D 28, no. 02 (January 2019): 1950041. http://dx.doi.org/10.1142/s021827181950041x.

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The hypothesis of the self-induced collapse of the inflaton wave function was introduced as a candidate for the physical process responsible for the emergence of inhomogeneity and anisotropy at all scales. In particular, we consider different proposal for the precise form of the dynamics of the inflaton wave function: (i) the GRW-type collapse schemes proposals based on spontaneous individual collapses which generate nonvanishing expectation values of various physical quantities taken as ansatz modifications of the standard inflationary scenario; (ii) the proposal based on a Continuous Spontaneous Localization (CSL) type modification of the Schrödinger evolution of the inflaton wave function, based on a natural choice of collapse operator. We perform a systematic analysis within the semi-classical gravity approximation, of the standing of those models considering a full quasi-de Sitter expansion scenario. We note that the predictions for the Cosmic Microwave Background (CMB) temperature and polarization spectrum differ slightly from those of the standard cosmological model. We also analyze these proposals with a Bayesian model comparison using recent CMB and Baryonic Acoustic Oscillations (BAO) data. Our results show a moderate preference of the joint CMB and BAO data for one of the studied collapse schemes model over the [Formula: see text]CDM one, while there is no preference when only CMB data are considered. Additionally, analysis using CMB data provide the same Bayesian evidence for both the CSL and Standard Models, i.e. the data have no preference between the simplicity of the LCDM model and the complexity of the collapse scenario.

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Majumdar, Arnab, Zoltán Hantos, József Tolnai, Harikrishnan Parameswaran, Robert Tepper, and Béla Suki. "Estimating the diameter of airways susceptible for collapse using crackle sound." Journal of Applied Physiology 107, no. 5 (November 2009): 1504–12. http://dx.doi.org/10.1152/japplphysiol.91117.2008.

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Airways that collapse during deflation generate a crackle sound when they reopen during subsequent reinflation. Since each crackle is associated with the reopening of a collapsed airway, the likelihood of an airway to be a crackle source is identical to its vulnerability to collapse. To investigate this vulnerability of airways to collapse, crackles were recorded during the first inflation of six excised rabbit lungs from the collapsed state, and subsequent reinflations from 5, 2, 1, and 0 cmH2O end-expiratory pressure levels. We derived a relationship between the amplitude of a crackle sound at the trachea and the generation number ( n) of the source airway where the crackle was generated. Using an asymmetrical tree model of the rabbit airways with elastic walls, airway vulnerability to collapse was also determined in terms of airway diameter D. During the reinflation from end-expiratory pressure = 0 cmH2O, the most vulnerable airways were estimated to be centered at n = 12 with a peak. Vulnerability in terms of D ranged between 0.1 and 1.3 mm, with a peak at 0.3 mm. During the inflation from the collapsed state, however, vulnerability was much less localized to a particular n or D, with maximum values of n = 8 and D = 0.75 mm. Numerical simulations using a tree model that incorporates airway opening and closing support these conclusions. Thus our results indicate that there are airways of a given range of diameters that can become unstable during deflation and vulnerable to collapse and subsequent injury.

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Masunaga, Hirohiko, Shoken M. Miyama, and Shu‐ichiro Inutsuka. "A Radiation Hydrodynamic Model for Protostellar Collapse. I. The First Collapse." Astrophysical Journal 495, no. 1 (March 1998): 346–69. http://dx.doi.org/10.1086/305281.

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Thiriet, M., M. Bonis, A. S. Adedjouma, and J. P. Yvon. "A Numerical Model of Expired Flow in a Monoalveolar Lung Model Subjected to Pressure Ramps." Journal of Biomechanical Engineering 111, no. 1 (February 1, 1989): 9–16. http://dx.doi.org/10.1115/1.3168349.

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A numerical investigation of pulmonary flow properties was carried out in a monoalveolar model composed of a balloon and a compliant tube in series, subjected to pressure ramps. The flow is shown to become quickly limited by a wave-speed mechanism, occurring at the peak flow. The critical point then travels upstream, while the main part of the exit flow rate is provided by the tube collapse. After the critical flow period, the flow becomes subcritical and viscous effects are predominant in the deeply collapsed tube.

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Zheng, Zhe, Yuan Tian, Zhebiao Yang, and Xinzheng Lu. "Hybrid Framework for Simulating Building Collapse and Ruin Scenarios Using Finite Element Method and Physics Engine." Applied Sciences 10, no. 12 (June 26, 2020): 4408. http://dx.doi.org/10.3390/app10124408.

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Reliable and high-fidelity virtual ruin scenarios for collapsed buildings are essential for post-earthquake emergency search and rescue training. However, the existing research on the distribution of ruins caused by building collapse is insufficient for supporting post-earthquake rescue training. Therefore, this paper proposes a hybrid framework for simulating building collapse and ruin scenarios, using a finite element (FE) model and a physics engine. Based on this framework, the following methods are proposed: (1) geometric model conversion from the FE model to the physics engine; (2) determination of the initial moment of collapse; and (3) data mapping of the FE simulation results. In addition, a corresponding program, Finite Element Method to Rigid Body Dynamics (FEM2RBD), is developed for the hybrid framework. The proposed framework simulates the entire process of building collapse and the distribution of ruins. The accuracy of the framework is validated using a shaking table test of a three-story reinforced concrete frame. The collapse process and ruin scenario of a real-world library building is simulated as a case study. The results show that the proposed framework combines the advantages of the FE model during the small-deformation stage with the advantages of physics engines during the large-deformation stage. The proposed framework can be valuable in simulating building collapse and ruin scenarios for post-earthquake rescue training.

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GREENSITE, J. "A MODEL OF QUANTUM GRAVITATIONAL COLLAPSE." International Journal of Modern Physics A 06, no. 15 (June 20, 1991): 2693–706. http://dx.doi.org/10.1142/s0217751x91001301.

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Some issues in the quantum mechanics of gravitational collapse are discussed in the framework of a simple minisuperspace model, consisting of a Friedman metric coupled to a massless scalar field. The model illustrates the role of intrinsic time coordinates in parametrizing gravitational collapse through a singularity, and the relevance of quantizing the metric scale factor over an infinite, rather than half-infinite, range.

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Taddei, Laura. "Spherical Collapse in the Symmetron Model." Journal of Physics: Conference Series 470 (December 6, 2013): 012006. http://dx.doi.org/10.1088/1742-6596/470/1/012006.

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Hennebelle, Patrick, Arnaud Belloche, Philippe André, and Anthony Whitworth. "Strongly triggered collapse model confronts observations." Proceedings of the International Astronomical Union 2, S237 (August 2006): 265–69. http://dx.doi.org/10.1017/s1743921307001585.

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AbstractDetailed modelling of individual protostellar condensations is important to test the various theories. Here we present comparisons between strongly induced collapse models with one young class-0 object, IRAS4A, in the Perseus cloud and one prestellar cloud observed in the Coalsack molecular cloud.

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Fryer, C. L. "Core-collapse model effects on nucleosynthesis." New Astronomy Reviews 48, no. 1-4 (February 2004): 13–17. http://dx.doi.org/10.1016/j.newar.2003.11.040.

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Pearle, Philip. "Relativistic collapse model with tachyonic features." Physical Review A 59, no. 1 (January 1999): 80–101. http://dx.doi.org/10.1103/physreva.59.80.

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Correia, João D., and John F. Wheater. "A simple model of dimensional collapse." Physics Letters B 388, no. 4 (November 1996): 707–12. http://dx.doi.org/10.1016/s0370-2693(96)01223-3.

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Wilkinson, Michael, Bernhard Mehlig, and Michael A. Morgan. "Shock fragmentation model for gravitational collapse." Research in Astronomy and Astrophysics 11, no. 5 (April 20, 2011): 545–62. http://dx.doi.org/10.1088/1674-4527/11/5/005.

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Carter, Michael J. "A Sociological Model of Societal Collapse." Comparative Sociology 12, no. 2 (2013): 236–54. http://dx.doi.org/10.1163/15691330-12341262.

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Abstract In his best-selling book Collapse, Jared Diamond employs a five-point framework that can be used to predict a society’s likelihood of declining from prosperity. These five points include 1. environmental damage, 2. climate change, 3. hostile neighbors, 4. friendly trade partners, and 5. a society’s response to its environmental problems. This paper re-interprets Jared Diamond’s model of societal collapse by using a sociological lens. Previous work in theoretical sociology is applied to Diamond’s framework to produce a predictive model of societal collapse. A path model and formal propositions are provided.

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Fuller, G. M., R. Mayle, and J. R. Wilson. "The Majoron model and stellar collapse." Astrophysical Journal 332 (September 1988): 826. http://dx.doi.org/10.1086/166695.

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Whitworth, A. P., and D. Ward‐Thompson. "An Empirical Model for Protostellar Collapse." Astrophysical Journal 547, no. 1 (January 20, 2001): 317–22. http://dx.doi.org/10.1086/318373.

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Morley, P. D., and I. Schmidt. "Platelet collapse model of pulsar glitches." Europhysics Letters (EPL) 33, no. 2 (January 10, 1996): 105–10. http://dx.doi.org/10.1209/epl/i1996-00306-3.

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Brown, Wilbur K. "A model of protogalactic cloud collapse." Astrophysics and Space Science 113, no. 1 (1985): 143–53. http://dx.doi.org/10.1007/bf00650277.

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Tian, Li, Wenming Wang, Ruisheng Ma, and Lei Wang. "Progressive Collapse Analysis of Power Transmission Tower Under Earthquake Excitation." Open Civil Engineering Journal 7, no. 1 (October 31, 2013): 164–69. http://dx.doi.org/10.2174/1874149501307010164.

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Collapses of power transmission towers had usually taken place in previous large earthquake. The collapse process of a power transmission tower under earthquake excitation is studied in this paper. Using international finite element software ABAQUS, the three-dimensional finite element model of the power transmission tower is created based on a practical engineering. Three typical seismic records are selected. The progress collapse processes of the power transmission tower under different seismic excitations are simulated using the nonlinear time history method. The collapse paths and failure positions of the power transmission tower are obtained under different seismic excitations. The results can provide reference for seismic design of power transmission tower which can prevent the collapse of the power transmission tower.

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Chi, En An, Chun Ming Xie, Ming Sheng Zhao, Jun Yang, and Tie Jun Tao. "The through Arch Rib Road Bridge Numerical Simulation of Blasting Demolition." Applied Mechanics and Materials 533 (February 2014): 175–80. http://dx.doi.org/10.4028/www.scientific.net/amm.533.175.

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In order to ensure one through arch rib road bridge blasting demolition will go well, using separate common node reinforced concrete model, numerical simulate the process of bridge collapsed and disintegrate, at the same time, analyze the stress state of steel and concrete unit in detail. The simulation results show that separate common node model could reflect the mechanical properties difference of steel and concrete materials; destruction of the support part of bridge and joint parts reserved , meanwhile, blasting treatment of the joint parts of derrick and arches, also arch center derrick and deck beams, arch springing hinge inside pier reserved on the left, it can ensure the bridge collapsed and broken fully, and can reduce the stack height of bridge collapsed in the river. The research considers that researching on structure collapse process by numerical simulation method not only reappear the process of collapse, but also forecast collapse result in schematic design phase. It will become the important means of study the structure mechanics process of blasting demolition and guide assisted the design of structure blasting demolition, which has important engineering practical value.

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Li, Yale, Zhouhong Zong, Bingwen Yang, Zhanghua Xia, Yuanzheng Lin, and Jin Lin. "Collapse Analysis of a Two-Span Reinforced Concrete Bridge Model." Applied Sciences 11, no. 19 (September 25, 2021): 8935. http://dx.doi.org/10.3390/app11198935.

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The continuous girder bridge is the main type of small- and medium-sized bridges; however, it has poor collapse resistance and suffers frequent earthquake damage. In order to grasp its collapse mechanism and clarify the internal and external factors affecting its collapse resistance, a 1:3-scaled, two-span bridge model subjected to shaking table test research was taken as the research object. The factors such as seismic characteristics, multi-directional seismic coupling, span, pier height, and structural system type were analyzed to determine the influences on the collapse mode of the bridge. The numerical results showed that different ground motion characteristics led to different collapse modes. Vertical ground motion had little effect on the structural response of the bridge. The change of span and pier height significantly changed the collapse resistance. A seismic isolation design could improve the anti-collapse performance, but the collapse mode varied with the system. The final anti-collapse design suggestions could provide reference for the seismic reinforcement of existing continuous girder bridges and the seismic design of continuous girder bridges that will be constructed.

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Qi, Qingjie, Xinlei Jia, Xinhua Zhou, and Youxin Zhao. "Instability-negative pressure loss model of gas drainage borehole and prevention technique: A case study." PLOS ONE 15, no. 11 (November 23, 2020): e0242719. http://dx.doi.org/10.1371/journal.pone.0242719.

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The internal collapse of deep seam drainage borehole and negative pressure loss represents a serious technical problem affecting gas drainage. To address this problem a creep model of coal around borehole was established based on the plastic softening characteristics of coal. The final collapse time of the borehole was determined and used to derive the three stages of the borehole collapse process. The model of negative pressure loss in drainage borehole was established according to the theory of fluid dynamics, the model of methane gas flow and the creep model of the coal around the borehole. The relationship between the negative pressure loss of drainage and the change of borehole aperture was derived, thereby revealing the main influencing factors of the negative pressure loss in the borehole. A drainage technique named “Full-hole deep screen mesh pipe” was introduced and tested to prevent the collapse of borehole and reduce the negative pressure loss. The result shows that after the borehole was drilled, the borehole wall was affected by the complex stress of the deep coal seam, the coal surrounding the borehole collapsed or presented the characteristics of creep extrusion towards the borehole. The “Full-hole deep screen mesh pipe drainage technology” could effectively control the collapse as well as the deformation of the borehole and reduced the negative pressure loss. Compared with the traditional drainage technology, the methane gas drainage concentration was increased by 101% and the gas flow was increased by 97% when the methane gas was drained for 90 days, the gas drainage efficiency increased significantly.

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Wang, Liang, Wei Lian Qu, Yan Fei Li, and Yi Fei Wang. "Transmission Tower Collapse Analysis with Wind Load Based on LS-DYNA." Advanced Materials Research 838-841 (November 2013): 370–74. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.370.

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Large span transmission tower is the lifeline of electricity transmission，Its collapse destroyed will causes adverse to the social and economic effects，The mechanism of the power transmission tower collapsed caused people's attention.The analysis is based on LS-DYNA program，explicit beam161 beam element is adopted to establish the finite element model for transmission towers，Analyses the collapse process of transmission tower and its failure mode with downburst load.

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Kangarlouei, Saeid Jabbarzadeh, and Morteza Motavassel . "The Comparison of the Ownership Structure at Different Level of the Financial Collapse in Listed Firms of Tehran Stock Exchange." Information Management and Business Review 4, no. 1 (January 15, 2012): 49–55. http://dx.doi.org/10.22610/imbr.v4i1.963.

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The main objective of this study is to compare ownership structure of different levels of collapse in listed companies of Tehran Stock Exchange (TSE). Study variables are the ownership structure that includes governmental ownership, private ownership (corporate ownership and individual ownership) and the different levels of collapse including latency stage, the stage of cash deficits and commercial and financial insolvency and complete collapse. Altman model (ZÂ´- Score) is used to predict the collapse of firm and Chi-Square test is used to test the research hypothesis. The study is the applied research and statistical population of study includes 96 collapse firms that are active in the TSE (subject to Business Law Article 141). Given the availability of financial information of distressed companies in 7 years between 2004-2010 years, a sample of 81 members was selected. The results show that the ownership structure of collapsed firms is independent from their different levels of collapse.

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Visser, Ruud, Ewine F. van Dishoeck, and Steven D. Doty. "Chemical History of Molecules in Circumstellar Disks." Proceedings of the International Astronomical Union 7, S280 (June 2011): 138–48. http://dx.doi.org/10.1017/s1743921311024938.

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AbstractThe chemical composition of a protoplanetary disk is determined not only by in situ chemical processes during the disk phase, but also by the history of the gas and dust before it accreted from the natal envelope. In order to understand the disk's chemical composition at the time of planet formation, especially in the midplane, one has to go back in time and retrace the chemistry to the molecular cloud that collapsed to form the disk and the central star. Here we present a new astrochemical model that aims to do just that. The model follows the core collapse and disk formation in two dimensions, which turns out to be a critical upgrade over older collapse models. We predict chemical stratification in the disk due to different physical conditions encountered along different streamlines. We argue that the disk-envelope accretion shock does not play a significant role for the material in the disk at the end of the collapse phase. Finally, our model suggests that complex organic species are formed on the grain surfaces at temperatures of 20 to 40 K, rather than in the gas phase in the T > 100 K hot corino.

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Jin, Jiani, and Liyang Chen. "Trinity Model of Ecological Management of Coal Mining Subsidence Area." Modern Economics & Management Forum 3, no. 3 (July 2, 2022): 214. http://dx.doi.org/10.32629/memf.v3i3.862.

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The mining of energy sources such as coal mines is extremely economical in the initial stage, but the collapse areas formed due to mining have also become an urgent problem, and S province has become one of the models for the exploration of the governance of such problems. Based on the literature study of other collapse area transformation, this paper takes the abandoned mine transformation forest park as an example, analyzes the current situation of collapse area governance through field research, systematically summarizes the operation model of mine transformation based on the analysis of coal mining collapse area BOT project, and constructs a comprehensive governance model of trinity of government, enterprise and society, hoping to bring some reference value for new ideas of collapse area governance.

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Tsuruta, Sachiko, Shing-Chi Leung, and Ken’ichi Nomoto. "The collapsar model of gamma ray burst central engine." International Journal of Modern Physics D 27, no. 05 (April 2018): 1830004. http://dx.doi.org/10.1142/s0218271818300045.

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Gamma ray bursts (GRBs) are the most explosive and brightest known photon sources in the universe. The initial bursts of GRBs found so far typically have a spectral peak between [Formula: see text][Formula: see text]keV and 1[Formula: see text]MeV. Most of their gamma ray prompt emissions last for [Formula: see text][Formula: see text]s or less. The jets ejected from ‘the central engine’ are thought to be responsible for these bursts. According to the currently accepted scenario, a black hole produced by the merger of compact objects (such as black holes and/or neutron stars) is responsible for shorter bursts while collapse of a massive star directly to a black hole produces longer bursts, although clear-cut distinction may not exist. In this paper, we consider the latter case, a collapsar model responsible for longer GRBs. They are more interesting in the sense that they are more energetic and hence their studies can be extended to first Population III GRBs, which may give some constraints on the understanding of the early universe. In this paper, we are interested mainly in the “central engine”, the region created by the collapse of a rotating massive star to a spinning black hole and its surrounding area created by the stellar remnant because the conditions of the jet propagation change once they are outside in the interstellar medium. We first follow the process of how a progenitor massive star collapses and forms a central disk-black hole system, how powerful jets are produced and ejected from that system, and how the jets propagate and penetrate the surrounding stellar medium. The continued journey of the jets outside the star and the mechanisms for GRB emissions are outside the scope of this short paper.

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Burlando, Massimiliano, Djordje Romanic, Giorgio Boni, Martina Lagasio, and Antonio Parodi. "Investigation of the Weather Conditions During the Collapse of the Morandi Bridge in Genoa on 14 August 2018 Using Field Observations and WRF Model." Atmosphere 11, no. 7 (July 7, 2020): 724. http://dx.doi.org/10.3390/atmos11070724.

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On 14 August 2018, Morandi Bridge in Genoa, Italy, collapsed to the ground that was 40 m below. This tragedy killed 43 people. Preliminary investigations indicated poor design, questionable building practices, and insufficient maintenance—or a combination of these factors—as a possible cause of the collapse. However, around the collapse time, a thunderstorm associated with strong winds, lightning, and rain also developed over the city. While it is unclear if this thunderstorm played a role in the collapse, the present study examines the weather conditions before and during the bridge collapse. The study particularly focuses on the analysis of a downburst that was observed around the collapse time and a few kilometers away from the bridge. Direct and remote sensing measurements are used to describe the evolution of the thunderstorm during its approached from the sea to the city. The Doppler lidar measurements allowed the reconstruction of the gust front shape and the evaluation of its displacement velocity of 6.6 m s−1 towards the lidar. The Weather Research and Forecasting simulations highlighted that it is still challenging to forecast localized thunderstorms with operational setups. The study has shown that assimilation of radar reflectivity improves the timing and reconstruction of the gust front observed by local measurements.

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King, Ivan R. "Observed Surface Densities in Globular Clusters." Symposium - International Astronomical Union 113 (1985): 1–17. http://dx.doi.org/10.1017/s0074180900147175.

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This review of observations is oriented toward the problem of core collapse in globular clusters. After a brief discussion of methods of determining surface densities, recent results are cited which show that the central brightness peak seen in M15 also appears in several other clusters. The central peaks of brightness are interpreted as the result of core collapse, which theories have repeatedly predicted. If binaries stabilize the collapsed core, the cluster should follow a Hénon model. In two of the three cases tested this model is a reasonable fit. Remaining theoretical questions are listed, as are observational needs.

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Wu, Di, Yihuai Liang, Yanxin Yang, and Jianjian Wu. "Study of the Subsidence Width Influence on the Geotextile Control of a Subgrade Collapse Based on a Half-Symmetric Model Test." Applied Sciences 12, no. 19 (September 22, 2022): 9504. http://dx.doi.org/10.3390/app12199504.

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The geotextile can be used to treat a subgrade collapse in karst areas. The subsidence width is an important factor affecting the geotextile to treat subgrade collapses. However, the available studies on the influence of the subsidence width on geotextile treatment settlement are limited. To study the effect of the subsidence width on the geotextile control of subgrade collapses, the half-symmetric model test had been established. To make up for the deficiencies of the model test, the optimized subsidence width was probed through a numerical calculation under ten different situations conducted by the finite element analyses. Previous full-section model test results were used to verify the rationality of the half-symmetric model and calibrate the input parameters of the numerical models. The influence of the subsidence width on soil pressure, tensile force and deformation of the geotextile, and soil settlement was analyzed. With the increase of the subsidence width, more loads of the subsidence area were transferred to a stable area via the geotextile, the vertical normal stress at the edge increased rapidly, the tensile force of the geotextile and vertical soil displacement in the subsidence area increased noticeably. When the anchorage ratio of L ≤ 2.0B, the geotextile fracture or soil failure occurred during the model test which indicated the geotextile treatment of the subgrade collapse was not suitable for projects with an anchorage ratio of L ≤ 2.0B. The geotextile might be reaching the limit of its tensile stiffness when the anchorage ratio of L = 2.22B. This is providing an insight into the treatment of a subgrade collapse in karst areas using geotextile.

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Zhang, Wei. "Research Status on the Collapse Mechanism and Prevention Measures of Mega Composite Structural Systems." MATEC Web of Conferences 175 (2018): 04008. http://dx.doi.org/10.1051/matecconf/201817504008.

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Mega composite structural system presents wide application prospects in high-rise and super high-rise buildings. However, research concerning the important issues of the seismic behavior, collapse mechanism, and prevention from progressive collapse for such new structural systems under severe earthquakes is quite limited. This paper will summarize the current research status, followed by the discussions on the collapse and prevention mechanisms of high-rise and super high-rise mega composite structural systems under severe earthquakes, the theoretical basis on progressive collapse mechanisms, numerical simulation techniques, and test methods. The failure modes of high-rise mega composite structures were studied firstly, followed by the collapse mechanisms and the associated criteria and indices. In addition, a new numerical technique for simulating the non-linear structural collapses considering large deformations will be presented, along with the relevant test results. This study shows that analysis method, damage accumulation model, failure criteria, appropriate preventive measures, and improved collapse experimental verification methods are all important seismic design considerations for high-rise and super high-rise mega composite structures. Based on the study results, recommendations for collapse and prevention mechanisms of high-rise buildings are proposed.

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Wu, Sheng-li, Chang-liang Fu, Cheng-song Liu, Jian Xu, and Ming-yin Kou. "Coke Collapse Model and Collapse Profile Variation Law for Bell-Less Top BF." Journal of Iron and Steel Research International 18, no. 10 (October 2011): 8–12. http://dx.doi.org/10.1016/s1006-706x(12)60014-4.

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Journal articles on the topic 'Collapse model'

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