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Inelastic and failure analysis of laminate structures by ABAQUS incorporated with a general constitutive relationship

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JOURNAL OF REINFORCED PLASTICS AND COMPOSITES 2007年第11期26卷 1135-1181页

作者： Huang, Zheng-Ming Tongji Univ Sch Aerosp Engn & Appl Mech Shanghai 200092 Peoples R China

A general constitutive relationship for describing the inelastic and strength behavior of laminated composites reinforced with various fiber preforms was presented in References [1,2]. The relationship is consistent in that when the fiber disappears or becomes the same as the matrix, the nonlinear constitutive equations of the resulting composite deteriorate to those of the isotropic matrix material. One of the best benefits of the constitutive relationship is that all the formulas involved are in explicit form and only the properties of the constituent fiber and matrix of the composite are required as input material data. This will significantly simplify a finite element analysis for a laminated structure. In the present paper, the general constitutive relationship for tape laminates was programmed into a user subroutine, UGENS, of the commercial finite element (FE) software ABAQUS. Several laminated structures including a complicated bone plate were then analyzed, and good correlation between the numerical results and available experimental data was found. A list of the original computer code together with an input data file was summarized in the appendixes of the paper.

关键词： laminated composite composite structure nonlinear behavior ultimate strength FEM analysis ABAQUS user subroutine computer code

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EFFECT OF STREAMER SHAPE AND DIMENSIONS ON LOCAL ELECTRIC-FIELD CONDITIONS

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IEEE TRANSACTIONS ON ELECTRICAL INSULATION 1988年第4期23卷 669-676页

作者： GIRDINIO, P MOLFINO, P MOLINARI, G VIVIANI, A FITZPATRICK, GJ FORSTER, EO SUNY BUFFALO DEPT ELECT ENGNBUFFALONY 14260 RUTGERS STATE UNIV DEPT PHYSNEWARKNJ 07102

Electrooptical studies of the streamer initiation process using high magnification are performed to determine streamer shapes and dimensions. Using this information, the local electrical field is computed by means of a sophisticated computer code, named COMPELL. A detailed description of several plausible primary streamer models and the numerical results obtained from the local field computations are reported. The results obtained show that the electric field in the immediate vicinity of the streamer tip is much higher than has been calculated or estimated earlier. The influence of the different shapes and dimensions of the modeled streamers on the electric field are shown and discussed.

关键词： discharges (electric) electric fields electrical engineering computing electro-optical effects COMPELL computer code electrooptical studies local electric field conditions primary streamer models streamer initiation streamer shape streamer tip Cathodes Electrodes Electromagnetic fields Finite difference methods Needles Numerical models Packaging Physics Shape Spatial resolution

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THRESHOLD CURRENT OF RIDGE WAVE-GUIDE LASER IN GAIN AND INDEX GUIDING REGIMES INCLUDING END FACET REFLECTIVITY

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IEE PROCEEDINGS-J OPTOELECTRONICS 1988年第2期135卷 159-165页

作者： BAVA, GP DEBERNARDI, PL MONTROSSET, I SCRIVANTI, M UNIV GENOVA DIBEI-16145 GENOVAITALY

In the paper we present the results of an efficient computer code that allows us to evaluate the ridge waveguide laser threshold current for quasi-TE and quasi-TM modes, including the effects of refractive index variation, produced by carriers, and end facet reflectivity. These two effects are taken into account in a new formulation, suitable to be integrated efficiently in the same computer code. Results for the threshold current in index and gain guided structures are presented, and compared within the framework of possible approximations.

关键词： Electronic engineering computing Semiconductor lasers computer code carriers electronic engineering computing index guiding regimes gain laser threshold current end facet reflectivity optical waveguides Design of specific laser systems Physics and chemistry computing physics computing semiconductor junction lasers quasi-TM modes ridge waveguide laser refractive index Lasing action in semiconductors

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Simulation and performance improvement of cryogenic distillation column, using enhanced predictive Peng-Robinson equation of state

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FLUID PHASE EQUILIBRIA 2019年 489卷 117-130页

作者： Larijani, Morteza Ardeshir Bayat, Mohamad Afshin, Hossein Sharif Univ Technol Sch Mech Engn CEEC Tehran Iran

In this study, a cryogenic distillation column has been designed and simulated via a computer code based on the theta method of convergence. The required thermodynamic properties are determined from the enhanced predictive Peng-Robinson (E-PPR 78) equation of state which has a good accuracy in predicting the corresponding thermodynamic properties of natural gas components. The combined code of distillation column/equation of state has been verified with that of another study. In the present study, the results are achieved by the constant molar over-flow and inclusion of energy equations assumptions. In order to have more accuracy in the results, the energy equations were considered in the column calculations. For improvement of column operational conditions, a parametric study is carried out. The results show that by the proper selection of reflux ratio, column operating pressure, feed plate location and considering energy constraints, the molar concentration of methane is decreased from 66.14% in the initial state to 13.75% in the improved state. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Cryogenic distillation column Enhanced predictive Peng-Robinson Parametric study Performance improvement computer code

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Recent advances for prediction of electric spark and shock sensitivities of organic compounds containing energetic functional groups to assess reliable models

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PROCESS SAFETY AND ENVIRONMENTAL PROTECTION 2019年 131卷 9-15页

作者： Keshavarz, Mohammad Hossein Damiri, Sajad Bagheri, Vahid Malek Ashtar Univ Technol Dept Chem POB 83145-115 Shahin Shahr Iran

For organic compounds containing energetic groups, electric spark (electrostatic or electrostatic discharge) and shock sensitivities can initiate their decomposition process in chemical industries and applications. Electrostatic charges often accumulate in bulk explosives and equipment during handling and processing procedures. They may provide hazardous explosion due to tribocharging. Since more reliable experimental methods have been developed in recent years for measurements of these sensitivities, some reliable methods have also been introduced for their predictions. This work reviews the recent models for prediction of electric spark sensitivity of some classes of organic and ionic liquid energetic compounds as well as shock sensitivity. A novel easy to handle and user-friendly computer code is also introduced to predict electric spark and shock sensitivities by suitable and reliable predictive methods for some classes of high explosives including polynitro arene and nitramine compounds. The computer code has been checked for some newly reported energetic compounds, where their experimental data were available, which provide reliable predictions. (C) 2019 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.

关键词： Organic energetic compound Electric spark sensitivity Shock sensitivity Hazard assessment computer code

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Stability analysis of the north-eastern slope of Daralou copper open pit mine against a secondary toppling failure

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ENGINEERING GEOLOGY 2019年 249卷 89-101页

作者： Amini, Mehdi Ardestani, Akbar Univ Tehran Coll Engn Sch Min Engn Northern Kargar St Tehran Iran

Secondary toppling failures have complicated mechanisms. In these instabilities, some natural or manmade external factors motivate and overturn a rock mass. One of the most common types of secondary toppling failures is slide-toe-toppling mode. When a blocky or layered rock mass is overlaid by a soil or weak rock mass, the combination of a toppling failure in the rock at the toe and a circular or non-circular sliding in the soil or weak rock in the top leads to this hybrid failure. In 2015, such failure occurred in north-eastern slope of Daralou copper open pit mine. During this instability, the slope consisted mainly of two 10-m benches and one 4-m semi-bench. Since it was supposed to excavate the slope to the depth of 54 m, experts were worried about the project facing a similar larger failure in the future. Hence, a widespread investigation was carried out on the failure. Firstly, the mechanism of this instability was clarified with geological and geotechnical surface and subsurface investigations. Next, existing analytical solution which had been presented for analysis of static slide-toe-toppling failure was modified and some new equations were obtained for analysis of the failure under dynamic condition. Then, a computer code was developed based on the new equations for evaluation of the instability. In the next step, the failed slope was analyzed using the code and finite element method, and outcomes of these analyses were compared with real conditions. The comparison showed that there was satisfactory agreement between the analytical, numerical and actual results. Therefore, these methods were used to predict the behavior of the final slope in static and dynamic conditions. These evaluations indicated that if displaced materials are completely excavated and removed from the mine and overall dip of the slope is reduced, the final slope will be stable against slide-toe-toppling failure. This paper summarizes the results and concludes that both the modified ana

关键词： Secondary toppling failure Analytic dynamic solution computer code Daralou copper open pit mine finite element

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The interaction of planar shock waves with multiphase saturated flexible porous materials - a numerical investigation

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JOURNAL OF FLUID MECHANICS 2006年 563卷 159-188页

作者： Levi-Hevroni, D. Levy, A. Ben-Dor, G. Sorek, S. Ben Gurion Univ Negev Dept Mech Engn Pearlstone Ctr Aeronaut Engn Studies IL-84105 Beer Sheva Israel Ben Gurion Univ Negev J Blaustein Desert Res Inst IL-84105 Beer Sheva Israel

The three-dimensional governing macroscopic equations of the flow field which is developed when an elasto-plastic highly deformable open-cell porous medium whose pores are uniformly filled with liquid and gas is struck head-on by a planar shock wave, are developed using a multiphase approach. The one-dimensional version of these equations is solved numerically using an arbitrary Lagrangian Eulerian (ALE) based numerical code. The numerical predictions are compared qualitatively to experimental results from various sources and good agreements are obtained. This study complements our earlier studies in which we solved, using an ALE-based numerical code, the one-dimensional governing equations of the flow field which is developed when an elasto-plastic flexible open-cell porous medium, capable of undergoing extremely large deformations, whose pores are saturated with gas only, is struck headon by a planar shock wave.

关键词： computer code MEDIA PROPAGATION EQUATIONS EVOLUTION PRESSURE SCHEMES

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Development of general nuclear resonance fluorescence model

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JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 2016年第11期53卷 1766-1773页

作者： Ogawa, Tatsuhiko Hashimoto, Shintaro Sato, Tatsuhiko Japan Atom Energy Agcy Res Grp Radiat Transport Anal Nucl Sci & Engn Res Ctr Div Environm & Radiat Sci Tokai Ibaraki Japan

A model to simulate nuclear resonance fluorescence (NRF) reactions of various nuclear species and their various excitation levels was developed. There is a strong need for the simulation of NRF applications using general purpose radiation transport codes;however, NRF reaction cross section data are available only for a few excited states for certain nuclear species. In this study, based on the generalized gamma de-excitation model, an NRF model that can simulate NRF reactions associated with all the levels included in the nuclear structure database was developed. Absorption cross sections calculated by the developed NRF model agree with the experimental data typically within one order of magnitude. To illustrate that this model can be used for simulation studies on NRF applications, the demonstration of the developed NRF model for non-destructive nuclear material assay and isomer production is shown.

关键词： Nuclear resonance fluorescence gamma ray cross section computer code isomer

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RESPECT - RAPID ELECTROMAGNETIC SCATTERING PREDICTOR FOR EXTREMELY COMPLEX TARGETS

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IEE PROCEEDINGS-F RADAR AND SIGNAL PROCESSING 1990年第4期137卷 214-220页

作者： TURNER, SD Admiralty Research Establishment Procurement Executive Ministry of Defence Chichester UK

To predict the radar cross-section (RCS) of a target, shadowing and multiple interaction effects must be taken into account. As the complexity of the target increases, the effort required to do this comes to dominate the calculation time. To cope with this problem, advanced ray-tracing techniques have been adapted from the field of computer graphics. The paper describes a computer code that combines these methods with high-frequency scattering theories (such as physical optics or the method of equivalent currents) to produce an RCS prediction tool for well defined complex targets. This program is then validated using measurements of known objects.

关键词： computer code Communications computing high-frequency scattering telecommunications computing extremely complex targets equivalent currents physical optics electromagnetic wave scattering RCS Radar theory multiple interaction effects rapid electromagnetic scattering predictor radar cross-sections shadowing radar cross-section

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SCREENING, PREDICTING, AND computer EXPERIMENTS

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TECHNOMETRICS 1992年第1期34卷 15-25页

作者： WELCH, WJ BUCK, RJ SACKS, J WYNN, HP MITCHELL, TJ MORRIS, MD CITY UNIV LONDON SCH MATH ACTUARIAL SCI & STAT LONDON EC1V 0HB ENGLAND NATL INST STAT SCI RES TRIANGLE PK NC 27709 USA OAK RIDGE NATL LAB DIV ENGN PHYS & MATH OAK RIDGE TN 37831 USA UNIV ILLINOIS DEPT CIVIL ENGN CHAMPAIGN IL 61820 USA

Many scientific phenomena are now investigated by complex computer models or codes. Given the input values, the code produces one or more outputs via a complex mathematical model. Often the code is expensive to run, and it may be necessary to build a computationally cheaper predictor to enable, for example, optimization of the inputs. If there are many input factors, an initial step in building a predictor is identifying (screening) the active factors. We model the output of the computer code as the realization of a stochastic process. This model has a number of advantages. First, it provides a statistical basis, via the likelihood, for a stepwise algorithm to determine the important factors. Second, it is very flexible, allowing nonlinear and interaction effects to emerge without explicitly modeling such effects. Third, the same data are used for screening and building the predictor, so expensive runs are efficiently used. We illustrate the methodology with two examples, both having 20 input variables. In these examples, we identify the important variables, detect curvature and interactions, and produce a useful predictor with 30-50 runs of the computer code.

关键词： computer code DATA-ADAPTIVE MODELING DIMENSION REDUCTION ELECTRONIC-CIRCUIT SIMULATION MAXIMUM LIKELIHOOD SIMULATION STOCHASTIC PROCESS

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