Dome Type Research Articles

Grid patterns optimization for single-layer latticed domes

In previous studies on optimized single-layer latticed domes, the inner space and external shape of the optimized dome is different from those of the initial dome. This difference may result in loss of structural functionality and aesthetics intended by the designers, making it difficult to separately evaluate the mechanical properties of the grid patterns and shape of the surface. In this study, 64 types of single-layer latticed domes having different geometric properties are optimized to obtain mechanically effective grid patterns. Six types of objective functions are employed. The nodal coordinates of the domes serve as the design variables under geometrical constraints, where the nodes of the domes can be shifted on the surface area. The geometric and mechanical properties of the optimized grid patterns are evaluated quantitatively against the objective functions. Moreover, interactions between the geometric and mechanical properties are investigated. The results show that the optimized grid pattern has superior mechanical properties and geometric imperfection sensitivity. This optimization scheme can be applied for designing mechanically effective grid patterns for single-layer latticed domes.

Formex algebra adaptation into parametric design tools and rotational grids

Abstract:This paper describes the adaptation of the formex configuration processing to the computer program Grasshopper 3D and focuses on the applied mathematical solutions. Formex algebra is a mathematical system, primarily used for planning structural systems like truss-grid domes and vaults, together with the programming language Formian. The goal of the research is to allow architects to plan truss-grid structures easily with parametric design tools based on the versatile formex algebra mathematical system. To produce regular structures, coordinate system transformations are used. Owing to the abilities of the parametric design software, it is possible to apply further modifications on the structures and gain special forms. The paper covers the basic dome types, and it introduces additional dome-based structures using special coordinate-system solutions based on a spherical coordinate system, vault structures and their modifications based on a cylindrical coordinate system and circular structures and their modifications based on polar coordinates. Moreover two rotational grid tools are introduced, which uses coordinate system transformations on a unique way to create surfaces of revolutions based on the given generating curve and create grid structures on these surfaces. It also describes the solution technique to implement the triangular grid version of every one of these tools based on diamatic domes. The adaptation of formex algebra and the parametric workflow of Grasshopper together give the possibility of quick and easy design and optimization of special truss-grid domes.

A Comparative Study of the Structural Performance of Different Types of Reticulated Dome Subjected to Distributed Loads

Whereas reticulated domes (i.e. domes composed of bars) are very material-efficient in general, the geodesic dome is claimed to be superior according to its patent holder, Richard Buckminster Fuller. Recent studies on the optimal design of reticulated domes do not allow a direct comparison between the geodesic dome and other dome types because the test cases are not subjected to the same loads. This paper aims to determine which type of reticulated dome is superior in terms of material efficiency by comparing the minimized weight of different dome types, taking into account stress and buckling constraints. The study includes hemispherical Schwedler, Kiewitt and geodesic domes with a diameter of 16 m, and a gravity load of 2 kN/m². Full enumeration is used to optimize the discrete variables (number of rings, subdivisions along each ring,...), while a gradient-based algorithm is used for the continuous variables (member sections). The results show that the claim of uniform stressing in a geodesic dome is legitimate: if all members are assigned the same size, a geodesic dome is generally more evenly stressed and up to 28% lighter than other dome types of similar size. However, if all members are sized individually, the Schwedler dome is the lightest.

The Analysis Of Biogas Fermentation Time From Cow Manure On Fixed Dome Biodigester Batch Systems

Biogas technology from cow manure in Indonesia has been developing for a long time, but the application of its use as an alternative energy source is not yet widely developed, due to various unknown operations and processes. This research aimed to analyzed of biogas fermentation time in batch system of cow manure. This research used a Fixed Dome type biodigester that had a total volume of 500 litters with its operating system in batches with 80% of the slurry containing cow manure and the rest for the gas chamber. The biogas fermentation time were 5, 10,15,20 25 and 30 days. The raw material from cow manure had an organic COD content of 10.240 mg / l with a pH of 6.7. The C/N feed ratio was set in the condition of 25: 1 and the ratio of slurry of cow manure with water was 1: 1. From the results of the study in batch process, it was found that the longer the fermentation time the higher the methane gas content but the methane gas content decreases on the 30 th day from 59,12% on the 25 th day to 50,04% on the 30 th day of fermentation.

Effect of filling frequency of substrate to optimized the production and quality of biogas as renewable energy

The study was aimed to optimized the biogas produced with compare the measurement of gas production, gas quality, temperature and pH of filling frequency that performed by every 3 days as treatment A and every 6 days as treatment B. This research observed on fixed dome type digester with the system of filling as continuously and has retention time for 16 days. The substrate consists of cow manure and water that homogenized. The result of the research using a t-test showed there were very significant differences [p <0.01] between treatment A and treatment B with an average of gas production on treatment A 9.75 ± 1.22 liters and treatment B 8, 72 ± 1.04 liters. Average of gas quality on treatment A 121.90 ± 3.86 watts and treatment B 113.59 ± 3.86 watts. Average of temperature on treatment A 28.12 ± 1.18°C and treatment B 27.25 ± 1.05°C. The average pH on treatment A was 6.68 ± 0.69 and treatment B was 7.37 ± 0.78. Based on the results can be concluded that the filing frequency of biogas substrate every 3 days is the best frequency to increase gas production and gas quality and to optimize the temperature and pH condition of slurry.

Real ear measurement (REM) and auditory performances with open, tulip and double closed dome in patients using hearing aids.

The aim of the study is to evaluate the importance of acoustic modifications generated by different commercially available ear-tips, focused on domes of receiver in the canal hearing aids using Real Ear Measurement (REM). We enrolled 110 people selecting 200 ears bearers of hearing aids. In every patient, we performed REM and audiological tests with three different dome types: Open, Tulip and Double Closed (DC). Data about real-ear occluded gain (REOG), Pure Tone Average (PTA), Word Recognition Score (WRS) with aids switched on in Free Field, Ear and Auditory Comfort were collected and analyzed. REOG gain was statistically significant different between the three types of dome, with a DC that always closes the external auditory canal (EAC) (p < 0.001). There was no statistically significant difference between the PTA (p = 0.11). Regarding the WRS there were statistically significant differences between Open and DC dome (p < 0.001) and between Tulip and DC dome (p < 0.001), with worse discrimination when using DC. Both auditory and ear comfort are worse in the DC than in the other two domes (p < 0.001). From measured REOG gain values, in 135 cases Tulip dome does not occlude the EAC, with a statistically significant difference compared to DC (p < 0.001; Odd Ratio 0.0012; 95% CI 0.001-0.0196). Our study confirms the necessity to perform REM to evaluate if the prescription target is achieved, especially when tulip domes are used, because they may not occlude the ear canal, causing in some cases the reduction of the vocal discrimination.

Effects of type of magnet attachment and implant angulation in two implant overdenture models.

PURPOSEThe purpose of this study is to evaluate the effects of type of magnet attachment and implant angulation in two implant overdenture models.MATERIALS AND METHODSMagnet attachments used in this study were flat and dome types (MGT5515, MGT5520D, Dentium Co., Seoul, Korea). Two implants with keepers were inserted in the resin blocks at a distance of 24 mm. For the first model, the implants were parallel to the vertical and perpendicular to the horizontal; for the second model, both were angulated 5 degrees to the mesial; for the third model, both were angulated 10 degrees toward the mesial. The retentive force was measured in both vertical and lateral directions. Statistical analyses were performed using SPSS software version 22.0 (α=.05).RESULTSThe flat type magnet attachment showed the highest lateral retentive force in the 20° divergent group (P<.05) and the dome type magnet attachment showed the highest lateral retentive force in the parallel group (P<.05). The vertical and lateral retentive force of the dome type magnet attachment was greater than that of the flat type magnet attachment in every direction (P<.05).CONCLUSIONWithin the limitations of this study, the dome shape magnet attachment can resist vertical and lateral retentive force more superiorly than the flat type magnet attachment, regardless of angle, in the mandibular two implant model.

Comparative Study on Multi-type Domes of Filament-Wound Composite Pressure Vessels

Filament-wound Composite Pressure Vessels (FCPV) have been used widely in the aerospace and commercial industries. Multi-type FCPVs have been applied to different mission scenes. In this paper, four types of domes (helical winding, helical winding ellipsoid, polar winding, polar winding ellipsoid) are studied based on a simplified parametric model, and a modified meridian computing method is employed for polar and helical winding domes after the inflection points. At last, four FCPV cases of different type of domes are calculated and discussed in detail. Results indicate that the parameters of the same winding pattern dome are similar, so it is suggested to use ellipsoid domes in prior for the convenience of fabrication and avoiding the inflection point at the meridian.

Critical design parameters of the electrode for liquid metal embrittlement cracking in resistance spot welding

The present work studied the influence of the geometric design of the electrode on Zn-assisted liquid metal embrittlement (LME) cracking during resistance spot welding (RSW). LME cracking of the galvannealed transformation-induced plasticity (TRIP) steel welds, induced by two types of electrodes, a radius type with different radius of curvature (R), and a dome type with variable tip diameter (d), was studied both experimentally and by simulation. The current density decreased and the contact area at the electrode/sheet (E/S) interface increased with the increasing R, resulting in low temperatures and thermal stress, which subsequently led to decreased LME tendency. On the contrary, the current density decreased but the initial contact area at the E/S interface remained unchanged with increasing d, causing only a minor reduction in the temperature and hence less influence on LME cracking. These results suggested that R is the most critical design parameter of the electrode that controls LME cracking. Moreover, the radius type electrode displayed lower LME sensitivity as compared with the dome type electrode. This is attributed to the fact that the radius type electrode provides the benefits of increase in both R and d.

Assessing the Effect of Dome Shape and Location on The Acoustical Performance of a Mosque by Using Computer Simulation

Architecturally, the dome is one evolutionary presence in most mosques of modern day. Besides mihrab, the dome is one of the architectural elements that has a phenomenon of concentration of energy by reflected sound waves from concave surfaces. The aim of this research is to compare the acoustical performance of different shapes of the dome and their respective locations by using geometrical approach computer simulation. Four types of dome that are commonly used on a mosque; Arabic, segmental, hemispherical, and onion, were modeled to compare their acoustical parameters i.e. reverberation time (RT) and speech transmission index (STI). It can be concluded that the shape of the dome does affect the RT. Furthermore, the shape of the dome also affects the STI - the larger the volume, the lower the STI value. However, the locations of a dome has little significance over acoustical parameter. The findings of this research may not limit to mosques only, but to any similar building that has similar typology.

Identification of critical members for progressive collapse analysis of single-layer latticed domes

This paper presents a method to identify the critical member in a single-layer latticed dome, which in the context of progressive collapse is defined as the member whose removal causes the most severe damage. The distribution of critical members in four typical types of single-layer latticed domes, including the Kiewit dome, the Ribbed dome, the Schwedler dome and the Lamella dome, is investigated through a comprehensive Alternate Path analysis scheme composed of hundreds of individual dynamic nonlinear analyses. The Alternate Path analyses also confirm the progressive collapse mechanism of single-layer latticed domes, i.e., the nodal snap-through buckling at either end of the initially removed member. On this basis, a critical member identification method is established, using an index that implicitly estimates the relative vulnerability to node buckling following the removal of a member to determine the criticality of this member. This method along with two other methods, using either static axial force or free vibration response, are evaluated via comparison against the nonlinear dynamic Alternate Path analysis results, and this proposed method shows a beyond-compare accuracy. Furthermore, based on the established understanding of the progressive collapse mechanism and the factors influencing the node buckling resistance, three methods for increasing the progressive collapse resistance of single-layer latticed domes are presented.

Investigating the jamming of particles in a three-dimensional fluid-driven flow via coupled CFD–DEM simulations

The clogging of a dense stream of particles when passing through an orifice occurs ubiquitously in both natural and industrial fields. Since most of the jamming phenomena lead to the negative effects, studying and preventing jamming is of great importance. There are two typical types of jamming due to different types of driving force: (a) gravity-driven jamming and (b) fluid-driven jamming. Among these two types of jamming, the fluid-driven jamming occurs in fluid-driven particle flows, and the initial solid concentration, the fluid velocity, and the orifice-particle size ratio has been demonstrated to have effects on the occurrence of this jamming. Although the individual influence of the initial solid concentration and orifice-particle size ratio on jamming has been studied, the coupled effects of these two factors on jamming are little known. In addition, the complex effects of the fluid velocity on jamming have not been fully discussed. To address these problems, this work performs a three-dimensional simulation of the fluid-driven jamming using the coupled Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) model. At first, the jamming probability under different initial conditions is studied. The jamming probability is displayed on the solid concentration–orifice size ratio plane to illustrate the coupled effects of these two factors on jamming. The simulation results show that the critical solid concentration, at which the jamming probability increases to 1, increases with the orifice-particle size ratio. This is because an orifice with a larger orifice size ratio has a greater particle discharge capacity, which allows more particles to pass through without jamming. Then, we reveal the influence of fluid velocity over a wide range on the fluid-driven jamming type, jamming probability and shape of the jamming dome. To the author’s knowledge, this is the first time that the shape of the jamming dome has been related to the fluid velocity. The jamming dome formed in the higher-speed flow has a greater curvature due to the greater fluid drag acting on the particles.

Gneiss Dome Formation in the Himalaya and southern Tibet

Abstract Gneiss domes in the Himalaya and southern Tibet record processes of crustal thickening, metamorphism, melting, deformation and exhumation during the convergence between the Indian and Eurasian plates. We review two types of gneiss domes: North Himalayan gneiss domes (NHGD) and later domes formed by orogen-parallel extension. Located in the southern Tibetan Plateau, the NHGD are cored by granite and gneiss, and mantled by the Tethyan sedimentary sequence. The footwall of these were extruded southwards from beneath the Tibetan Plateau and subsequently warped into a domal shape. The second class of domes were formed during displacement on normal-sense shear zones and detachments that accommodated orogen-parallel extension during the Late Miocene. In some cases, formation of these domes involved an early stage of southwards-directed extrusion prior to doming. We review evidence for orogen-parallel extension to provide context for the formation of these gneiss domes. Compilations of pressure–temperature–time–deformation data and temperature–time paths indicate differences between dome types, and we accordingly propose new terminology. Type 1 domes are characterized by doming as an artefact of post-high-temperature exhumation processes in the Middle Miocene. Type 2 domes formed in response to exhumation during orogen-parallel extension in the Late Miocene that potentially post-dates south-directed extrusion.

Уникальный купольный дом

The definition of the domed house is given. Its obvious advantages in comparison with the house in the form of a parallelepiped are revealed. It is shown that the domed house surpasses the usual parallelepiped house in almost all considered parameters: the internal volume of the house, strength, heat loss, construction materials consumption, construction speed, financial costs, natural lighting, air aeration inside the building, climate and seismic resistance, appearance. Comparison of the main types of domes of a dome house is made: geodesic, stratodesic and monolithic concrete, which determine the technology of erecting a domed house. The four main technologies for building domed houses that are used in construction are described: dome construction based on a geodetic sphere, erecting a house on the basis of a pneumoframe, domed house on the basis of fixed formwork and the technology of erecting a domed house, which is a prefabricated construction of the factory production of water. Comparative characteristics of the methods for erecting a domed house are given, advantages and disadvantages of each method of building a domed house are described. The negative moments in the construction and operation of the domed house are determined: the complexity of dome calculations, the lack of practice of dome construction, the large amount of building materials waste, the use of non-standard doors, windows, furniture, the unusualness and fear of owners of a domed house in a unique house. Practical recommendations for eliminating flaws in the domed house are indicated: purchase of finished projects, attraction to construction of a dome house of professional builder. Conclusions are made about the prospects of domed houses due to their capacity and stability, geometric symmetry of shapes and strength, speed of erection and uniqueness for any region of Russia.

Experimental Investigation of Novel Fixed Dome Type Biogas Plant using Gas Recovery Chamber in Rural Areas of Pakistan

Energy is the lifeblood of modern civilization. Pakistan is facing an acute energy crisis due to dependence on fossil fuels having economical as well as environmental consequences. Biogas is  viable alternative energy source to tackle the problem of this energy crisis in agriculture-based developing countries like Pakistan. The present study is designed to enhance the gas production by using the gas recovery chamber. Gas recovery chamber is a small digester that requires less initial cost compared to two-stage digestion. Moreover, the boost in fermentation time of bacteria in acetogenisis and methanogenisis is about 5 days using the gas recovery chamber. Due to this technique, an increase in 21.5% gas production is achieved as compared to the conventional biogas plant, simultaneously decreasing the payback period of this plant . This recovery chamber utilizes maximum methanogens bacteria for fermentation under climatic conditions of Pakistan. This investigation shows recent improvement in the anaerobic digestion processes that have led to greater biogas production.

Prestress Design of Ellipsoid Hybrid Form and Parameter Analysis of Design Factors

AbstractNew types of hybrid cable domes combining Geiger and Levy forms are presented in this paper. Their basic configuration and geometry are proposed and discussed. The partition-assembly method...

Pre-stressing method and structural behaviour of a Tensairity dome with multiple inflated cushions

This paper describes a novel type of Tensairity dome, which is composed of a tensegrity cable dome and several inflated cushions. The cushions and cable dome act as a whole in synergy, and the introduction of compressed air, which is an important part of the structure, extends the tensegrity concept. This study builds an illustrative numerical model and examines the feasibility of the proposed structure. The inflating amount of air for each cushion and influence of the inflating sequence are considered. The effect of the internal air pressure on the structural behaviour is investigated for several different load cases. The results demonstrate that pre-stressing can be introduced by inflating the cushions instead of the tensioning cables, which greatly facilitates the construction. The novel structure exhibits effective stiffness and integrity in several possible conditions, and the internal air pressure of approximately 500–3500 Pa can ensure the tensioning role of the cushions. The air pressure values should be determined according to the environmental conditions of the construction site.

Change in Public Concern and Responsive Behaviors Toward Air Pollution Under the Dome.

This study evaluates the effect of the documentary Under the Dome on the concern and responsive behaviors of the public regarding air pollution in China, with two surveys conducted before and after watching the documentary. Employing difference-in-differences regression, this study answers two research questions: (1) Does Under the Dome change public concern about air pollution? (2) Does Under the Dome change public behaviors in response to air pollution, including protective behaviors (i.e., wearing face masks) and mitigation behaviors (i.e., reducing car driving)? We find that the information campaign (1) protects against the decline of public concern about air pollution in Beijing and (2) moderates the degree to which people's perceived severity, perceived susceptibility, and sense of self-efficacy influence protective behaviors and moderates the degree to which people's belief in the cooperative behaviors by others influences mitigation behaviors. This study provides evidence that information campaigns of the Under the Dome type are effective in raising public awareness; however, the information campaign did not directly influence public protective and mitigation behaviors.

Assessment of Dome Building Damage and Repair Method

The paper deals with the assessment of the damage of a concrete dome type of structure and the method of repairment. Due to own weight of the dome, the concrete portion of the dome near bottom rim is in tension and the steel reinforcement was not sufficiently provided, causing cracks at bottom and leakage at top of dome. UPV tests, profometer tests and core drilling were carried out to observe the condition of existing dome. Testing results were used as bases for constructing repairment method, epoxy grout, epoxy mortar and the use of carbon fibre reinforced plastic (CFRP).

Various Response Functions in Lattice Domes Reliability Via Analytical Integration and Finite Element Method

The main aim of this work is to verify an influence of the response function type in direct symbolic derivation of the probabilistic moments and coefficients of the structural state variables of axisymmetric spherical steel dome structures. The second purpose is to compare four various types of domes (ribbed, Schwedler, geodesic as well as diamatic) in the context of time-independent reliability assessment in the presence of an uncertainty in the structural steel Young modulus. We have considered various analytical response functions to approximate fundamental eigenfrequencies, critical load multiplier, global extreme vertical and horizontal displacements as well as local deformations. Particular values of the reliability indices calculated here can be of further assistance in the reliability assessment by comparing the minimal one with its counterpart given in the Eurocode depending upon the durability class, reference period and the given limit state type.