scholarly journals Symmetric Shape Transformations of Folded Shell Roofs Determining Creative and Rational Shaping of Building Free Forms

Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1438 ◽  
Author(s):  
Jacek Abramczyk ◽  
Aleksandra Prokopska
Keyword(s):  
Mechanical Properties ◽  
Initial Stresses ◽  
Shape Transformation ◽  
Interdisciplinary Problems ◽  
Parametric Description ◽  
Roof Shells ◽  
Unconventional Methods ◽  
Corrugated Shells ◽  
Half Length ◽  
Symmetric Shape

The paper presents an innovative approach to solving interdisciplinary problems emerging in the design process of building free forms roofed with elastically transformed corrugated shells. The effectiveness and rationality of shaping such free forms and the creativeness in searching for the parametric forms require the application of their regular and symmetric models which have to be derived from the geometric and mechanical properties of the rationally transformed subsequent folds of these shells. Simplified smooth models used for engineering developments and accurate folded models implemented for scientific research have to be created by means of unconventional methods different from those presented in classical courses. Owing to the variety of the forms of the proposed innovative reference tetrahedrons and their parametric description, the algorithms developed by the authors have to be implemented in computer programs. The rationality of the transformed roof shells, revealed in the limitation of the level of the fold’s initial stresses resulting from the shape transformation, and the attractiveness of these forms are achieved by the axial symmetry and contraction of each shell fold at its half-length. The symmetries adopted in the process of modeling such roof shells are also exploited by the discussed new method to obtain coherent unconventional general forms of entire buildings.

Innovative Building Forms Determined by Orthotropic Properties of Folded Sheets Transformed Into Roof Shells

2020 ◽  
Vol 61 (2) ◽  
pp. 111-124
Author(s):  
Aleksandra Prokopska ◽  
Jacek Abramczyk
Keyword(s):  
Computational Models ◽  
High Sensitivity ◽  
Free Form ◽  
Shape Transformation ◽  
Steel Sheets ◽  
Shape Transformations ◽  
Thin Walled ◽  
Orthotropic Properties ◽  
Roof Shells ◽  
Qualitative And Quantitative Characteristics

Qualitative and quantitative characteristics of geometrical and mechanical changes of nominally plane steel sheets folded in one direction, caused by big elastic shape transformations were invented on the basis of the authors' tests, analyzes and computational models of thin-walled folded sheets transformed into shell shapes. Both geometrical and mechanical changes produce significant restrictions in using sheets for shell forms. The deliberate transformations and sheets' characteristics are required to obtain attractive and innovative forms of roof shells and their consistent structures as well as entire buildings. The search for effective solutions related to free forms of buildings and shape transformations of sheets especially in the fields of: shape transformation, effort and stabilization of their walls is necessary due to the high sensitivity of thin-walled open profiles to boundary conditions and loads. A method for shaping such free form buildings that effectively exploit specific orthotropic properties of the transformed sheeting is presented.

Geometry of Modular Origami Metamaterials

2017 ◽  
Author(s):  
Yunfang Yang ◽  
Zhong You
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Expansion Ratio ◽  
Mechanism Analysis ◽  
Shape Transformation ◽  
Design Flexibility ◽  
Fundamental Research

Modular origami is a type of origami where multiple pieces of paper are folded into modules, and these modules are then interlocked with each other forming an assembly. Some of them turn out to be capable of large scale shape transformation, making them ideal to create metamaterials with tuned mechanical properties. In this paper, we carry out a fundamental research on 2D modular origami assemblies using mathematical tiling and patterns and mechanism analysis, which leads to the development of various patterns consisting of interconnected quadrilateral modules. Due to the existence of 4R linkages within the patterns, they become transformable, and can be compactly packaged. Moreover, by the introduction of paired modules, we are able to adjust the expansion ratio of the pattern. Additionally, we also show that transformable patterns with higher mobility exist for other polygonal modules. Our findings provide more design flexibility to achieve truly programmable metamaterials.

Unconventional Methods of Sintering Inconel 718 MIM Samples

2016 ◽  
Vol 716 ◽  
pp. 830-839
Author(s):  
Olivier Dugauguez ◽  
Jose Manuel Torralba ◽  
Thierry Barrière ◽  
Jean Claude Gelin
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Heating Rate ◽  
Inconel 718 ◽  
Fine Particle ◽  
Alloy Powder ◽  
Microwave Sintering ◽  
Conventional Sintering ◽  
Unconventional Methods ◽  
Super Alloy

In this investigation, three different ways of sintering Inconel 718 MIM samples are compared. The conventional way of sintering in a furnace will be compared to FAHP and microwave sintering. The difficulty of these two methods is to be able to control the shrinkage of the sample and so its shape. These methods have yet not been investigated with a super alloy powder and so, the effects of a high sintering rate on a MIM sample. By accelerating the sintering kinetics, the thermal behavior may be modified. Hence, the behavior of the Inconel 718 sintered by field assisted and microwave sintering has been investigated. The sintered samples were all injected from a feedstock composed of a fine particle Inconel powder and a binder principally composed of CAB and PEG. They were debinded into water for 24h and put in a furnace at 500°C during 2 hours. The heating rate of the furnace was set to 5°C/min until 1290°C during 2 hours. The heating rate of the FAHP was set to 50°C/min until 1250°C during 15 minutes. The microwave samples were sintered around 1300°C during 1 hour, the temperature was increased progressively by steps of 100°C. The effects of the different process on the microstructure and the mechanical properties are then compared. There was no difference in distribution of pores between the conventional sintering and the FAHP sintering but a finer grain size showed better hardness. The microwave sintering of a MIM sample is more complex and the best properties were not obtained.

scholarly journals Parametric Creative Design of Building Free-forms Roofed with Transformed Shells Introducing Architect’s and Civil Engineer’s Responsible Artistic Concepts

Buildings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 58 ◽  
Author(s):  
Jacek Abramczyk ◽  
Aleksandra Prokopska
Keyword(s):  
Spatial Reasoning ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Mutual Position ◽  
Software Applications ◽  
Single Structure ◽  
Interdisciplinary Problems ◽  
Engineering Models ◽  
Parametric Description ◽  
Effective Design

The article concerns a parametric description of unconventional building forms roofed with folded sheeting transformed elastically into shells. The description supports the designer in the search for attractive forms and a rational use of materials. The adoption of strictly defined sets of initial parameters determines the diversification of the designed architectural free-forms. An impact of selected proportions between these parameters on these forms is illustrated by an example of a single structure. Folded elevations and a segmented shell roof make each such structure internally coherent and externally sensitive. The mutual position and proportions of the shape of all elements, such as the roof, eaves, and façades, along with regular patterns in the same structure, determine this consistency of its form and sensitivity to harmonious incorporation into the natural or built environments. The study is a new insight into shaping free-forms of buildings in which the modern and ecological materials determine the important shape and mechanical limitations of these forms. With a skillful approach, the materials allow their extensive use in buildings. However, various interdisciplinary problems related to architectural shaping of free-forms and static and strength work thin-walled shell sheeting roofs must be solved. For effective design it is necessary to use relevant software applications, where spatial reasoning is crucial for ordering the three-dimensional space by means of simplified engineering models.

Hybrid hydrogel sheets that undergo pre-programmed shape transformations

Soft Matter ◽  
2014 ◽  
Vol 10 (41) ◽  
pp. 8157-8162 ◽  
Author(s):  
Zengjiang Wei ◽  
Zheng Jia ◽  
Jasmin Athas ◽  
Chaoyang Wang ◽  
Srinivasa R. Raghavan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shape Transformation ◽  
Hybrid Hydrogel ◽  
Shape Transformations ◽  
Out Of Plane ◽  
Novel Strategy

This communication describes a novel strategy to achieve programmable shape transformation of hybrid hydrogel sheets by modulating both the in-plane and out-of-plane mismatches in mechanical properties.

scholarly journals Geometry of Transformable Metamaterials Inspired by Modular Origami

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
Yunfang Yang ◽  
Zhong You
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Expansion Ratio ◽  
Mechanism Analysis ◽  
Two Dimensional ◽  
Shape Transformation ◽  
Design Flexibility ◽  
Fundamental Research

Modular origami is a type of origami where multiple pieces of paper are folded into modules, and these modules are then interlocked with each other forming an assembly. Some of them turn out to be capable of large-scale shape transformation, making them ideal to create metamaterials with tuned mechanical properties. In this paper, we carry out a fundamental research on two-dimensional (2D) transformable assemblies inspired by modular origami. Using mathematical tiling and patterns and mechanism analysis, we are able to develop various structures consisting of interconnected quadrilateral modules. Due to the existence of 4R linkages within the assemblies, they become transformable, and can be compactly packaged. Moreover, by the introduction of paired modules, we are able to adjust the expansion ratio of the pattern. Moreover, we also show that transformable patterns with higher mobility exist for other polygonal modules. The design flexibility among these structures makes them ideal to be used for creation of truly programmable metamaterials.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

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