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1.
A constitutive model that captures the material behavior under a wide range of loading conditions is essential for simulating complex boundary value problems. In recent years, some attempts have been made to develop constitutive models for finite element analysis using self‐learning simulation (SelfSim). Self‐learning simulation is an inverse analysis technique that extracts material behavior from some boundary measurements (eg, load and displacement). In the heart of the self‐learning framework is a neural network which is used to train and develop a constitutive model that represents the material behavior. It is generally known that neural networks suffer from a number of drawbacks. This paper utilizes evolutionary polynomial regression (EPR) in the framework of SelfSim within an automation process which is coded in Matlab environment. EPR is a hybrid data mining technique that uses a combination of a genetic algorithm and the least square method to search for mathematical equations to represent the behavior of a system. Two strategies of material modeling have been considered in the SelfSim‐based finite element analysis. These include a total stress‐strain strategy applied to analysis of a truss structure using synthetic measurement data and an incremental stress‐strain strategy applied to simulation of triaxial tests using experimental data. The results show that effective and accurate constitutive models can be developed from the proposed EPR‐based self‐learning finite element method. The EPR‐based self‐learning FEM can provide accurate predictions to engineering problems. The main advantages of using EPR over neural network are highlighted. 相似文献
2.
Modelling blue and green water resources availability in Iran 总被引：7，自引：0，他引：7
Knowledge of the internal renewable water resources of a country is strategic information which is needed for long‐term planning of a nation's water and food security, among many other needs. New modelling tools allow this quantification with high spatial and temporal resolution. In this study we used the program Soil and Water Assessment Tool (SWAT) in combination with the Sequential Uncertainty Fitting program (SUFI‐2) to calibrate and validate a hydrologic model of Iran based on river discharges and wheat yield, taking into consideration dam operations and irrigation practices. Uncertainty analyses were also performed to assess the model performance. The results were quite satisfactory for most of the rivers across the country. We quantified all components of the water balance including blue water flow (water yield plus deep aquifer recharge), green water flow (actual and potential evapotranspiration) and green water storage (soil moisture) at sub‐basin level with monthly time‐steps. The spatially aggregated water resources and simulated yield compared well with the existing data. The study period was 1990–2002 for calibration and 1980–1989 for validation. The results show that irrigation practices have a significant impact on the water balances of the provinces with irrigated agriculture. Concerning the staple food crop in the country, 55% of irrigated wheat and 57% of rain‐fed wheat are produced every year in water‐scarce regions. The vulnerable situation of water resources availability has serious implications for the country's food security, and the looming impact of climate change could only worsen the situation. This study provides a strong basis for further studies concerning the water and food security and the water resources management strategies in the country and a unified approach for the analysis of blue and green water in other arid and semi‐arid countries. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
3.
Monireh POSHTKOOHI 《地球学报》2012,33(S1):55-57
The Iranian plateau comprises several continental blocks, which are clearly bounded by major faults. The sedimentary, stratigraphic, magmatic and metamorphic features of these blocks vary from one to the other. The continental crust of subject area in Central Iran was investigated in the past by several authors. It was concluded that this zone was metamorphosed, intruded by granites and faulted during late Precambrian Pan-African Orogeny (Ramezani and Tucker, 2003). 相似文献
4.
K. Bazargani-Guilani M. A. Nekouvaght Tak† M. Faramarzi 《Australian Journal of Earth Sciences》2013,60(3):297-307
A multidisciplinary study including geology, petrography and reconnaissance isotope analyses has been carried out on the Reza-Abad, Reza-Barak and Heydar-Abad Pb–Zn deposits, hosted by different types of Cretaceous dolostone and limestone in northeast of the city of Shahmirzad in the central Alborz region of Iran. Dolostones are dominated by replacement dolomite with minor dolomite cements. The studied deposits are strata-bound vein and breccia type and are associated with tensional faults and fractures. Mineralisation occurs in veins and in karstic and tectonic breccias. Hypogene minerals include galena with minor sphalerite and pyrite. Supergene minerals comprise Fe-oxide, cerussite, anglesite, plattnerite, minimum and mimetite. Calcite, quartz and dolomite form gangue minerals. The δ18O and δ13C values of dolomites vary between –5.8 and +2.1‰ VPDB and between 0.0 and +2.9‰ VPDB, respectively. Isotopic and previous fluid inclusion studies suggest that deposits formed from brines (15–25 wt.% NaCl equiv.) at temperatures of 70 to 110°C. Lead isotope data are homogeneous and represent upper crust source. This study provides an insight into the ore-forming processes of MVT deposits in the northeast Shahmirzad region. 相似文献
5.
An RES-Based Model for Risk Assessment and Prediction of Backbreak in Bench Blasting 总被引：1，自引：1，他引：0
F. Faramarzi M. A. Ebrahimi Farsangi H. Mansouri 《Rock Mechanics and Rock Engineering》2013,46(4):877-887
Most blasting operations are associated with various forms of energy loss, emerging as environmental side effects of rock blasting, such as flyrock, vibration, airblast, and backbreak. Backbreak is an adverse phenomenon in rock blasting operations, which imposes risk and increases operation expenses because of safety reduction due to the instability of walls, poor fragmentation, and uneven burden in subsequent blasts. In this paper, based on the basic concepts of a rock engineering systems (RES) approach, a new model for the prediction of backbreak and the risk associated with a blast is presented. The newly suggested model involves 16 effective parameters on backbreak due to blasting, while retaining simplicity as well. The data for 30 blasts, carried out at Sungun copper mine, western Iran, were used to predict backbreak and the level of risk corresponding to each blast by the RES-based model. The results obtained were compared with the backbreak measured for each blast, which showed that the level of risk achieved is in consistence with the backbreak measured. The maximum level of risk [vulnerability index (VI) = 60] was associated with blast No. 2, for which the corresponding average backbreak was the highest achieved (9.25 m). Also, for blasts with levels of risk under 40, the minimum average backbreaks (<4 m) were observed. Furthermore, to evaluate the model performance for backbreak prediction, the coefficient of correlation (R 2) and root mean square error (RMSE) of the model were calculated (R 2 = 0.8; RMSE = 1.07), indicating the good performance of the model. 相似文献
6.
Twana Kamal Haji Asaad Faramarzi Nicole Metje David Chapman Farough Rahimzadeh 《国际地质力学数值与分析法杂志》2020,44(3):418-431
The accurate modelling of gravity is of crucial importance for a variety of issues including, but not restricted to, the identification of buried objects. Gravity is an unbounded problem, which causes challenges when applying numerical models, i..e.., it results in computational difficulties when specifying the relevant boundary conditions. In order to address this, previous research has tended to generate artificial boundary conditions, e.g., truncating the simulated domain and adding many unrealistic zero-density layers, which introduces more unknown parameters and unnecessarily excessive computational time. In order to overcome such inaccuracies, this paper proposes an innovative development of the finite element modelling technique, which represents a step change in the field of gravity forward modelling. A comprehensive formulation of an infinite element to reproduce the far-field boundary effect using only one layer of infinite elements is presented. The developed model considerably reduces the computational time while obtaining high degrees of accuracy. The model is validated against the exact solution of the problem, and its results show an excellent performance. The proposed method can significantly improve the postprocessing and interpretation stages of data analysis relevant to micro-gravity sensors. The new method is applied to subsurface civil engineering although its applicability is manifold. 相似文献
7.
In northeastern Sanandaj-Sirjan structural zone, the Takab-Ghorveh belt comprises a volcanic province which related to the collision between the Eurasian and Arabian continents. It contains almost Quaternary andesitic basalt to alkali basalt. These alkali basaltes show Strombolian type eruptions. The volcanic rocks in Bijar area represent a range of mafic magmas, re-vealed by mingling and mixing textures. A variety of features suggest that the lava flows before eruption from magma chambers, contaminated by continental crust. 相似文献
8.
Monireh POSHTKOOHI 《地球学报》2009,30(Z1):50-60
The study area is located in the northern part of Sanandaj-Sirjan zone in western part of Hamedan province in Iran. Estimation of times of these events is based on the 40K–40Ar age determination carried mainly on separated amphiboles, biotites and muscovites, and interpreted as the ages of their isotopic closure. Estimations range between 91 and 70 Ma (A. Baharifar et al., 2004). The Sanandaj–Sirjan zone of western Iran is a metamorphic belt (greenschist–amphibolite facies) that uplifted during late Cretaceous continental collision between the Afro-Arabian continent and the Iranian micro-continent. The Alvand plutonic mass is the most important aspect of igneous phenomena of this area. The plutonic rocks are generally confined to granitoidic such as granite, alkali-granite, monzodiorite, diorite, monzodioritic gabbro, monzogabbro, pegmatite, aplite etc according to IUGS clas-sification. 相似文献
9.
Monireh Poshtkoohi Talat Ahmad Ashwini Kumar Choudhary 《Journal of Earth System Science》2018,127(5):72
Precambrian magmatism in the Biabanak-Bafq district represents an extensive sequence of mafic magmatic rocks. Major, trace and rare earth elements reveal that the low-Ti basement mafic rocks are magnesium tholeiite and low-Ti cover a mafic rock belongs to Fe-tholeiite, whereas, the high-Ti alkaline mafic rocks, as well as dolerites, show much more Fe–Ti enrichment. Primitive mantle normalized trace element patterns show a relative enrichment of LREE and LILE and depletion of HFSE, but have an equally distinct continental signature reflected by marked negative Nb, Sr, P, and Ti anomalies. The composition of the intrusive rocks is consistent with fractional crystallization of olivine ± clinopyroxene ± plagioclase, whereas variations in the Sr and Nd isotope compositions suggest heterogeneous sources and crustal contamination. Low-Ti group samples contain a crustal signature in the form of high La/Yb, Zr/Nb, and negative \(\varepsilon \hbox {Nd}\) values. In contrast, high-Ti mafic magmatic rocks display an increase in La/Yb with a decrease in Proterozoic alkaline rocks recognized across the central Iran. The presence of diverse mafic magmatic rocks probably reflects heterogeneous nature of sub-continental lithospheric mantle (SCLM) source. The mafic magmatism largely represents magmatic arc or rift tectonic setting. It is suggested that the SCLM sources were enriched by subduction processes and asthenospheric upwelling. 相似文献
10.
Zabih Alah Rostami Seyed Ali Al-modaresi Hassan Fathizad Marzban Faramarzi 《Arabian Journal of Geosciences》2016,9(17):685
Landslides are introduced as regional movements, which influence different engineering structures such as roads, railways, and dams and cause the person’s death. Identification of landslide zones may decrease the financial losses and human injuries or deaths. This study tries to achieve a landslide susceptibility mapping in Cham-gardalan catchment by weighting the main criteria and the membership functions of fuzzy logic. For this, we applied the best relationship function between the presence and absence of landslides as well as a collection of the elements. At first, the landslide points were identified by the means of some components those of satellite images, topographical (1:50,000) and geographical (1:100,000) maps, field visits, and Google Earth software followed by the preparation of landslide distribution maps. Then, all effective landslide factors such as percentage of slope, slope aspect, height, geology, land uses, distance from roads, distance from drainages, distance from breakage, and precipitation map have been utilized in order to conduct the fuzzy analyses. Landslide susceptibility map was performed by fuzzy operators (Gamma, Product, Sum, Or, And) in the study area. After fuzzificating and weighting, the effective criteria of landslides were determined through fuzzy Gamma operators with the landaus of 0.2, 0.5, 0.8, and 0.9 and by comparing final maps for making an appropriate model of landslide susceptibility mapping. The regional susceptibility map represents the landslide-prone areas in five categories those of very low, low, moderate, high, and very high. Our results indicated that among the applied operators, Gamma with landau of 0.9 can be used as an appropriate method for mapping the landslide susceptibility due to the suitable fuzzification of given criteria based on landslide distribution maps. In addition, the elements of road, percentage of slope, distance from drainage, and geology were recognized as the most important factors for occurring the landslides. 相似文献