scholarly journals Analysis of Cylindrical Masonry Shell in St. Jacob`s Church in Dolenja Trebuša, Slovenia—Case Study

Buildings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 127 ◽  
Author(s):  
Mojmir Uranjek ◽  
Tadej Lorenci ◽  
Matjaž Skrinar
Keyword(s):  
Shell Structure ◽  
Seismic Loading ◽  
Vertical Displacement ◽  
Crack Pattern ◽  
Shell Structures ◽  
Combined Stress ◽  
Load Bearing Capacity ◽  
Stress States ◽  
Membrane Bending

This paper focuses on identifying key reasons for the damage of the cylindrical masonry shell structure in St. Jacob`s church in Dolenja Trebuša, Slovenia. Typical damage patterns which can be formed in shell structures and may affect the load bearing capacity are outlined. Several stress states (membrane, bending and also combined stress state) that can occur in the shell structure are described. Load cases such as the vertical displacement of the support structure, temperature loading, weight of maintenance team and also seismic loading are taken into account in order to identify the actual cause for the registered crack pattern in the shell structure. Analysis of the shell structure is performed using the SAP2000 structural software. Based on the obtained results, which highlighted key reasons for registered damage, the monitoring of cracks is recommended in the first phase, and, in continuation, the most appropriate repair and strengthening measures are proposed.

scholarly journals A SERS Study of Charge Transfer Process in Au Nanorod–MBA@Cu2O Assemblies: Effect of Length to Diameter Ratio of Au Nanorods

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 867
Author(s):  
Lin Guo ◽  
Zhu Mao ◽  
Sila Jin ◽  
Lin Zhu ◽  
Junqi Zhao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Shell Structure ◽  
Shell Structures ◽  
Core Shell ◽  
Absorption Bands ◽  
Au Nanorods ◽  
The Core ◽  
Band Position ◽  
Surface Enhanced Raman ◽  
Core Shell Structure

Surface-enhanced Raman scattering (SERS) is a powerful tool in charge transfer (CT) process research. By analyzing the relative intensity of the characteristic bands in the bridging molecules, one can obtain detailed information about the CT between two materials. Herein, we synthesized a series of Au nanorods (NRs) with different length-to-diameter ratios (L/Ds) and used these Au NRs to prepare a series of core–shell structures with the same Cu2O thicknesses to form Au NR–4-mercaptobenzoic acid (MBA)@Cu2O core–shell structures. Surface plasmon resonance (SPR) absorption bands were adjusted by tuning the L/Ds of Au NR cores in these assemblies. SERS spectra of the core-shell structure were obtained under 633 and 785 nm laser excitations, and on the basis of the differences in the relative band strengths of these SERS spectra detected with the as-synthesized assemblies, we calculated the CT degree of the core–shell structure. We explored whether the Cu2O conduction band and valence band position and the SPR absorption band position together affect the CT process in the core–shell structure. In this work, we found that the specific surface area of the Au NRs could influence the CT process in Au NR–MBA@Cu2O core–shell structures, which has rarely been discussed before.

DIGITAL FABRICATION AS A LEARNING MEDIA FOR LIGHTWEIGHT STRUCTURE WITH CASE STUDY OF SHELL STRUCTURE

MODUL ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 126-133
Author(s):  
Stephanus Evert Indrawan ◽  
LMF Purwanto
Keyword(s):  
Shell Structure ◽  
Laser Cutting ◽  
Digital Fabrication ◽  
Scalar Model ◽  
Structure System ◽  
Lightweight Structures ◽  
Digital Devices ◽  
Lightweight Structure ◽  
Realization Process

The lightweight structure system is an effort to optimize the structure to distribute the load efficiently. Unfortunately, students often have difficulty imagining the learning outcomes application in the real world when studying light structural systems. However, the use of the scalar model can still explain several essential aspects of a lightweight structural system, one of which is the effect of connection and formation of material components on the structural capability. Therefore, this paper aims to bridge the learning process by utilizing digital devices from the concept stage of structural modeling with the help of software (Rhinoceros, Grasshopper, and Kangaroo) to the realization process using laser cutting. The method used is a semi-experimental method that applies Hooke's law principle, which produces a shell structure system with a digital fabrication approach that utilizes a lightweight material, namely, corrugated paper board, as the primary material. This paper concludes that digital technology and digital fabrication processes can help students understand the concept of lightweight structures because they can use computer simulations, cut them using laser cutting, and assemble them in the field in a series of simultaneous processes. 

scholarly journals Effect of Combined Stress on Yield and Fracture Behavior of Zircaloy-2

1961 ◽  
Vol 83 (4) ◽  
pp. 499-508 ◽  
Author(s):  
R. L. Mehan
Keyword(s):  
Plastic Flow ◽  
Biaxial Tension ◽  
Effective Strain ◽  
Tension Stress ◽  
Combined Stress ◽  
Flow Properties ◽  
Axial Tension ◽  
Fracture Ductility ◽  
Stress States ◽  
Single Stress

The yielding and fracture characteristics of Zircaloy-2 as a function of stress state were investigated at room temperature through the medium of thin-walled cylindrical specimens under internal pressure and axial tension. Stress states from uniaxial longitudinal tension to uniaxial tangential tension were examined. Two tests at elevated temperature were performed at a single stress ratio. It was found that the fracture ductility lessened with increasing biaxiality. A minimum in ductility was found at balanced biaxial tension where the fracture ductility, as expressed by the effective strain, was 29 per cent. The yielding and plastic flow properties were found to be highly anisotropic. Two methods were used to express the plastic flow data: a graphical approach and a theoretical analysis based on a theory proposed by R. Hill, either one of which is suitable to express the flow properties of Zircaloy-2 under various states of combined stress.

Asymmetric Postbuckling Behavior of Hemispherical Shell Structure Under Axial Compression

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Shanshuai Wang ◽  
Shuhui Li ◽  
Ji He ◽  
Yixi Zhao
Keyword(s):  
Stainless Steel ◽  
Axial Compression ◽  
Shell Structure ◽  
Load Capacity ◽  
Plastic Hinge ◽  
Shell Structures ◽  
Postbuckling Behavior ◽  
Asymmetric Deformation ◽  
Deformation Stage ◽  
Hemispherical Shell

In real physical experiments, three typical deformation stages including elastic deformation stage, symmetric deformation stage, and asymmetric deformation stage appear step by step when the stainless steel hemispherical shell structure is under axial compression loading. During the asymmetric deformation stage, the rolling-plastic-hinge-radius which characterizes the size of the deformation area evolves along the circumferential direction with the compressive displacement. For the hemispherical shell structures with apparent asymmetric deformation stage, the double-buckling phenomenon of the structures in experiments can be clearly detected. The traditional theoretical analysis based on the assumption with circumferentially constant rolling-plastic-hinge-radius is not suitable to predict this phenomenon. For these hemispherical shell structures, load capacity and absorbed energy predicted by the traditional analysis are usually higher than experimental results in the asymmetric deformation stage. In this paper, a new description based on experimental observation for the evolution of rolling-plastic-hinge-radius has been proposed. Minimum energy principle was employed to obtain the postbuckling behavior. The energy evolution of different buckling stages during compression loading is investigated to evaluate the structure load capacity. Stainless steel hemispherical specimens with different sizes are tested under axial compression between two rigid plates to verify the theoretical modification. Good agreement is achieved between proposed model and experimental results. The theoretical model proposed in this paper can be used in prediction of postbuckling behavior for different deformation patterns in the asymmetric deformation stage. It also provides higher flexibility and efficiency for the postbuckling behavior prediction of hemispherical shell structures.

scholarly journals Molecular dynamics study on the formation of self-organized core/shell structures in the Pb alloy at the nanoscale

RSC Advances ◽  
2017 ◽  
Vol 7 (84) ◽  
pp. 53509-53515 ◽  
Author(s):  
Tao Li ◽  
ZhiChao Wang ◽  
YunRui Duan ◽  
Jie Li ◽  
Hui Li
Keyword(s):  
Molecular Dynamics ◽  
Shell Structure ◽  
Shell Structures ◽  
Core Shell ◽  
Self Organized ◽  
Core Shell Structure

An abnormal self-organized core/shell structure is formed in the liquid Al–Pb alloy, which can be controlled by confined conditions.

Case-Study on the Application of Precast Double-Curved Concrete Elements for the Green Planet Shell Structure

2017 ◽  
pp. 2494-2502
Author(s):  
Sietse Witterholt ◽  
Roel Schipper ◽  
Steffen Grünewald ◽  
Pierre Hoogenboom ◽  
Rob Nijsse ◽  
...  
Keyword(s):  
Shell Structure ◽  
Concrete Elements

Long Term Structural Integrity Considerations for Abandoned Pipelines

2016 ◽  
Author(s):  
Shane Finneran ◽  
T. J. Prewitt ◽  
Joel Kaufman
Keyword(s):  
Transmission Lines ◽  
Structural Integrity ◽  
Large Diameter ◽  
Metal Loss ◽  
Finite Element Analyses ◽  
Load Bearing Capacity ◽  
Soil Subsidence ◽  
Structural Capacity

There has been increasing interest across the industry to better understand the possible long term risks associated with out of service pipelines. In Canada, the Canadian Energy Pipeline Association (CEPA), Petroleum Technology Alliance of Canada (PTAC), and the National Energy Board (NEB), have undertaken multiple studies to identify and assess the threats related to pipeline abandonment. [1][2][3] The primary hazards typically identified across industry for pipeline abandonment are associated with long term corrosion degradation, potential for creation of water conduits, possible environmental impacts, and potential for pipeline collapse and associated soil subsidence. Unfortunately, little guidance is presently available to the industry for determining remaining structural capacity of a heavily corroded pipeline to establish likelihood, and possible timeline, of collapse, nor for determining possible subsidence magnitudes associated with large diameter transmission lines. This paper presents a technical case study for an assessment approximating the remaining strength of an abandoned pipeline subject to long term corrosion degradation, considering both general metal loss, and randomized pitting and perforation growth. The work presented used a combination of finite element analyses, and existing industry models for determining load bearing capacity of an abandoned pipeline under varying levels of degradation.

scholarly journals Research on Biomimetic Models and Nanomechanical Behaviour of Membranous Wings of Chinese Bee Apis cerana cerana Fabricius

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Yanru Zhao ◽  
Dongsheng Wang ◽  
Jin Tong ◽  
Jiyu Sun ◽  
Jin Zhang
Keyword(s):  
Finite Element ◽  
Apis Cerana ◽  
Element Model ◽  
Apis Cerana Cerana ◽  
Technical Innovation ◽  
Uniform Load ◽  
Load Bearing Capacity ◽  
Concentrated Force ◽  
Stress States ◽  
The Finite Element Model

The structures combining the veins and membranes of membranous wings of the Chinese bee Apis cerana cerana Fabricius into a whole have excellent load-resisting capacity. The membranous wings of Chinese bees were taken as research objects and the mechanical properties of a biomimetic model of membranous wings as targets. In order to understand and learn from the biosystem and then make technical innovation, the membranous wings of Chinese bees were simulated and analysed with reverse engineering and finite element method. The deformations and stress states of the finite element model of membranous wings were researched under the concentrated force, uniform load, and torque. It was found that the whole model deforms evenly and there are no unusual deformations arising. The displacements and deformations are small and transform uniformly. It was indicated that the veins and membranes combine well into a whole to transmit loads effectively, which illustrates the membranous wings of Chinese bees having excellent integral mechanical behaviour and structure stiffness. The realization of structure models of the membranous wings of Chinese bees and analysis of the relativity of structures and performances or functions will provide an inspiration for designing biomimetic thin-film materials with superior load-bearing capacity.

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