DOMES—一个已开发的调度操作管理专家系统

本文介绍了东南大学与安徽省调度中心用PROLOG语言合作研制开发的调度操作管理专家系统—DOMES,它能正确开出安徽省调所必需的各类调度命令票与操作票,并已在IBM-AT-286上成功地投入运行。本文描述了DOMJJ的结构、性能与功能,介绍了其数据库与规则库,简要讨论了该专家系统的进一步扩展与作用。

Coherence of wind pressure on domes

The concept of the coherence function is adopted to find the wind pressure correlation of two points on domes of different rise-span ratios. The pressure measurements are made on the dome roof models by the wind tunnel test. The coherence functions for different separation distances at several directions of the domes from different wind directions are examined. The results show that there is a strong correlation for two adjacent points at low frequency, but not for non-adjacent points. The coherence of the wind pressure increases with the decrease in the separation distance. Moreover, the coherence of the wind pressure is in the strongest correlation on the along-wind direction at the same separation, but the lowest correlation is on the cross-wind direction. The detailed derivation of the proposed exponential coherence model of the wind pressure from experimental data is also discussed. It is found that the proposed exponential coherence model can be appropriate, especially, for small separations and the change in the directions on domes. Based on the quasi-steady theory, the relationship between the wind pressure and the wind velocity on the basis of the coherence model is also examined. The coherence observed between the wind pressure and the wind velocity is not adequately predicted by the quasi-steady theory.

Failure Modes for Single-Layer Reticulated Domes Under Impact Loads

The paper presents the theory of Hamilton variation principle which is the current method for impact problem, central difference method which is efficient solution of finite element (FE) method for impact problem and adapts to solve non-linear dynamic problem. And it introduces the ANSYS/LS-DYNA which is the popular FE software for impact problem both at home and abroad. Then it gives solutions for one simple model by analytical method and ANSYS/LS-DYNA respec-tively to validate function of software, and they are consistent. Afterward, it gives model of single-layer Kiewitt reticulated dome with a span of 60 m, and the cylinder impactor, and introduces the contact interface arithmetic, especially the material model of steel (piecewise linear plasticity model) which takes stain rate into account and makes steel failure stress higher under impact loads. The vertical displacement, stress in main members, and the plastic deformation for dome under impact loads were obtained. Then four failure modes (no failure, moderate failure, global failure and slight failure) were summarized according to the rules of dynamic response. And the characteristics of dynamic response for each failure mode were shown.

Failure Process and Energy Transmission for Single-Layer Reticulated Domes Under Impact Loads

No failure, moderate failure, severe failure, and slight failure are the four failure modes generalized observed in the dynamic response of the single-layer reticulated dome under vertical impact load on apex. TE (the time that the end of impact force) and TF (the time that members are broken) are two key times in the failure process. Characteristics of dynamic responses at the two key times are shown in order to make the failure mechanism clear. Then three steps of energy transfer are summarized, i.e. energy applying, energy loss and energy transfer, energy consump-tion. Based on the three steps, energy transfer process for the failure reticulated dome under once impact is introduced. Energy transmissibility and local loss ratio are put forward firstly to obtain EL F(the energy left in the main reticulated dome) from the initial kinetic energy of impactor. More-over, the distribution of failure modes is decided by EL F which leads to the maximum dynamic re-sponse of the reticulated dome, but not by the initial impact kinetic energy of impactor.

Damage mechanism of single-layer reticulated domes under severe earthquakes

To study the damage mechanism of single-layer reticulated domes subject to severe earthquakes, three limit states of single-layer reticulated domes under earthquakes are defined firstly in this paper. Then, two failure modes are presented by analyzing damage behaviors, and their characteristics are pointed out respectively. Furthermore, the damage process is analyzed and the causes of structural damage in different levels are studied. Finally, by comparing deformation and vibration status of domes with different failure modes, the principles of different failures are revealed and an integrated frame of damage mechanism is set up.

Preliminary analysis of mode truncation of single-layered reticulated domes under earthquakes

In anti-seismic calculation, the mode truncation is a significant problem to engineers if the mode-superposition response spectrum method is used, which has not been completely solved yet in some large and complex structures such as reticulated domes. In this case, some useful advices, concentrating on the problem above, are expected through a careful and comprehensive investigation of this paper. During the investigation, the authors first point out shortcomings of former researches. Then frequency-spectrum characteristics of single-layered reticulated domes were studied from the perspective of structural responses. During this process, some important results such as the existence of the main resonant section, and the fact that the relative sensitivity of these domes under horizontal and vertical impulse varies with the different R/S ratios were achieved. Furthermore, based on the study of frequency-spectrum characteristics, as well as that of earthquake input, reasonable numbers of mode truncation in single layered reticulated domes with different R/S ratio were presented. Results of case studies prove the mode truncation number proposed is valid.

RESEARCH ON IMPERFECTION SENSITIVE REGION OF SINGLE-LAYER LATTICED DOMES

The concept of the imperfection sensitive region is given. The advanced stochastic imperfection method is used to research the imperfection sensitive region of single-layer latticed domes. Taking a K6 single-layer latticed dome with a diameter of 50 m as an example, its imperfection sensitive region is made up of the first 12 kinds of joints. The influence of the imperfections of support joints on the stability of the K6 single-layer latticed dome is negligible. Influences of the joint imperfections of the main rib and the secondary rib on the structural stability are similar. The initial deviations of these joints all greatly lower the critical load of the dome. Results show that the method can analyze the structural imperfection sensitive region quantitatively and accurately.

Seabed domes with circular depressions in the North Yellow Sea

Numerous isolated shallow seabed domes with depressions were discovered in the North Yellow Sea in a high-resolution multibeam echosounder survey. Twelve domes were located within a 11 km by 17 km survey area. The domes in this area were between 0.1 m and 1.0 m high with diameters ranging from 250 to 1 700 m. They were surrounded by corresponding depressions and displayed characteristic shapes ranging from circular to elliptical. The acoustic anomalies displayed on the high resolution sub-bottom profile images demonstrated that shallow gas accumulated just beneath these domes, suggesting that the migration and accumulation of the shallow gas caused the formation of these features. Accumulation atop the seabed domes and erosion within the depressions, as indicated by the lithological features of the sediment cores, suggested that seabed bottom currents also played a role in the formation and evolution of these features. In addition, the simultaneous decrease in the chlorite and sulfate content in core d pore water samples confirmed the presence of submarine fresh/brackish groundwater, which is of interest for hydrological budgets and may be a significant component of the regional hydrologic balance. Our findings suggested that shallow gas accumulation and migration are likely coupled to localized groundwater discharge at this domed site.

Geometrical nonlinear stability analyses of cable-truss domes

The nonlinear finite element method is used to analyze the geometrical nonlinear stability of cable truss domes with different cable distributions. The results indicate that the critical load increases evidently when cables, especially diagonal cables, are distributed in the structure. The critical loads of the structure at different rise span ratios are also discussed in this paper. It was shown that the effect of the tensional cable is more evident at small rise span ratio. The buckling of the structure is characterized by a global collapse at small rise span ratio; that the torsional buckling of the radial truss occurs at big rise span ratio; and that at proper rise span ratio, the global collapse and the lateral buckling of the truss occur nearly simultaneously.

The PTst Evolution of Metamorphism and Development Mechanism of the Thermal-Structural-Gneiss Domes in the Chinese Altaides

A series of thermal-structural-gneiss domes (briefly TSG domes) are developed in the Chinese Altaides. Sericite-chlorite zone, biotite zone, garnet zone, staurolite zone, kyanite (andalusite)zone, sillimanite- cordierite (sillimanite-garnet)zone, migmatite zone and migmatic granite- gneiss field are developed from the low-grade metamorphic area to the centre of the TSG domes. The succession of the formation and evolution of the progressive metamorphic zone, migmatite zone and migmatic granite-gneiss corresponds to the spatial sequence from the outer part to the centre of the TSG domes. The peak temperature of the metamorphism and granitization increases progressively from 400℃ to 800℃ while the pressure decreases progressively from 1.05 GPa to 0.10 GPa from the biotite zone to the migmatic granite-gneiss field. The metamorphism of the erogenic belt may be described by the pressure-temperature-space-time model (PTst). In the main episode of orogeny, the deep heat flow and structural flow upsurged along a series of the centres of the regional thermodynamic anomalies, giving rise to the progressive metamorphism, granitization, and the differential uplift and the formation of TSG domes.

Non-Diapiric Salt Domes in the West Zanjan, Central Iran

The salt domes of the west Zanjan (Central Iran) are the most important structures in the study area. They have been formed by the uplifting and erosion together under low humidity and dry and warm climate condition. The salt rocks with near to 200 meters thickness are related to lower member of the Upper Red Formation (Early Miocene) that deposited in the inverted back arc basin. They have been formed in the Central Iran basin after the Arabian-Eurasian convergence. Based on filed works and preparation of geologic map, salt domes have been cropped out during regional uplifting and erosion along hinge zone of a longitudinal anticline. Also, there is no evidence for salt diapirism and so, they are different from some salt diapirs in the southwestern margin of Zanjan that is investigated by other researchers.

Shape Optimization and Assessment of Wind Induced Stresses in Domes

Domes are popularly used for column free areas. They are employed as covers to reservoirs and treatment units and also as containment in nuclear reactors. Inverted domes are popular as foundations. Structures are built with an intended end use for a specified utility period. The functional requirement is to serve the purpose and the structural requirement constitutes stability, strength, safety, serviceability and durability. Satisfaction of these requirements at affordable costs is the goal of structural optimization. This paper demonstrates the need and scope for optimization of domes by formulating and solving the problem by use of calculus （volume of material is the objective function being minimized using first principles of calculus）. A simple but elegant method is suggested for determination of wind stresses by statics which compares very well with that obtained by rigorous method.

The Impact of Geometrical Structure of Domes on the Acoustic Performance within Mosques

Mosques are considered as one of the most significant architectures for Muslim,where they have evolved to attain the Islamic requirements.Various worship activities are done within these public architectures and these activities required various acoustical needs.The geometry of mosques and their ceiling is largely impacted on the acoustical characteristics.The domes are the most shape that utilized to construct the mosque ceiling.The geometric architecture of the domes represents one of the key factors that impact on the performance of acoustics within the mosque.Thus,this paper aims to determine the impact of geometric architecture of domes on the quality of acoustical characteristics within the mosque.The mosque of King Abullah has been selected as a case study to address this issue.Further,many mosques have been studied from the literature to determine the impact of the geometrical structure of the domes on the acoustic characteristics and speech intelligibility.Many parameters have been utilized to measure the acoustical performance like RT,clarity,dome volume,dome shape,dome height and the material utilized to cover the dome surfaces.Based on the studies within the literature and the case study within this paper,the impact of the geometrical structure of the domes has been determined,also the impact of these parameters on the sound quality within the mosque has been determined at the end of this paper.

Dynamic Response of 100m, 200m, 300m Lattice Domes with LRB Seismic Isolator

The objective of this study is to analyze the seismic response characteristics of 100 m, 200 m, 300 m spanned lattice domes under both horizontal and up-down ground motion of El Centro earthquake. For the analysis of earthquake response of lattice domes, the time history analysis is used for the estimation of the dynamic response. Horizontal and up-down earthquake ground motions cause a large asymmetric vertical deformation in the large spatial domes. This study is to investigate the seismic characteristics of lattice domes for eigenvalue modes, displacement and acceleration response. The earthquake response of lattice domes with LRB (lead rubber bearing) isolation device by the horizontal and up-down combined ground motion is significantly reduced for the asymmetric vertical deformation and accelerations of domes.

Structural Systems Composed of Concentric Hoops and Designed for Lightweight Domes of Large Spans

The paper presents a selected group of tension-strut structural systems designed for the construction of lightweight dome covers of large spans, which can be comparatively easy to assembly and have rises of which can be relatively small. This will allow significant decrease costs of erection and maintenance of objects covered by these roof structures. The proposed systems have been obtained from the results of suitable transformations of a chosen type of double-layer space frame and an appropriate arrangement of tetrahedron modules in the space of each of the newly designed type of the structural system. All these systems are built by means of concentric hoops having their own integral spatial stiffness obtained after an appropriate pre-stressing. Particular hoops can be mounted on the ground level and then one by one will be hoisted to the designed positions where they will be connected by means of special sets of the tension members. Due to these structural features, the assembly process of each system should be relatively simple, fast and not expensive. The whole tension-strut structure has to be connected to the compression perimeter ring and suitably pre-stressed. There are presented visualizations of the proposed systems prepared on the basis of the appropriate numerical models especially defined for each particular structure.

Proposition and design of a new Micro-Architected Domes family:A biomimicry-based approach

In the last decade,micro-architected structures have gained significant attention in academia and industry for their lightweight,strong,and thermally efficient properties.Inspired by biomimicry design,this paper presents a novel ribbed family of additively manufactured Micro-Architected Domes(MAD).The design incorporates tetrapod pyramid unit cells,golden ratio-based fractal patterns,Schoen’s Minimal Gyroid,and spherical geometry.The study focuses on dome radius,height,and azimuth/elevation partitioning as input variables,with the main output being ribbed micro-cell diameter.The relationships between unit-cells’diameter and input variables were established through problem-solving and numerical computations:linear dependency with the dome radius and hyperbolic dependency with the azimuth and elevation partitioning.The proposed design successfully adhered to the Surface-to-Volume ratio of Schoen’s Minimal Gyroid,achieving an average volume relative density of 2.5%,confirming its lightweight nature.The feasibility of the design was further supported by fabricating three specimens using Filament Fused Fabrication.This research showcases the potential of biomimicry-inspired micro-architected structures,paving the way for innovative applications in various fields.

Technical reports and theoretical studies about the structural behaviour of masonry domes in the 18th century

The development of the scientific theory on the stability of vaulted structures was driven mainly during the 18th century based on applying the laws of Mechanics and the knowledge of the properties of materials.In the specific case of structures such as domes,the development of the theory is closely related to the theory of arches and vaults.Still,the main contributions are made in technical reports on the construction,stability,and repair of domes,such as the dome of Saint Peter’s in Rome and Sainte-Genevie`ve or Pantheon in Paris.This article,therefore,analyses the relationship between theory and practice and the development achieved in the specific subject of masonry domes during the 18th century from the point of view of the Limit Analysis of Masonry Structures.In a more general sense,the objective of this research is to study in greater depth the theory of Limit Analysis itself,that is,to learn from the work carried out in the 18th century by mathematicians,architects,and engineers,who,although unaware of the existence of the theoretical framework of Limit Analysis as such,moved within it.