Computational Issues in Multifield, Multiscale and Three-Dimensional Structural Engineering

2015 ◽  
pp. 1-41
Author(s):  
C.E. Majorana ◽  
V.A. Salomoni ◽  
G. Xotta ◽  
B. Pomaro ◽  
G. Mazzucco
Keyword(s):  
Structural Engineering ◽  
Three Dimensional

scholarly journals On the forces that cable webs under tension can support and how to design cable webs to channel stresses

2019 ◽  
Vol 475 (2223) ◽  
pp. 20180781 ◽  
Author(s):  
Guy Bouchitté ◽  
Ornella Mattei ◽  
Graeme W. Milton ◽  
Pierre Seppecher
Keyword(s):  
Linear Programming ◽  
Convex Hull ◽  
Structural Engineering ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Finite Dimensional ◽  
Necessary And Sufficient

In many applications of structural engineering, the following question arises: given a set of forces f 1 ,  f 2 , …,  f N applied at prescribed points x 1 ,  x 2 , …,  x N , under what constraints on the forces does there exist a truss structure (or wire web) with all elements under tension that supports these forces? Here we provide answer to such a question for any configuration of the terminal points x 1 ,  x 2 , …,  x N in the two- and three-dimensional cases. Specifically, the existence of a web is guaranteed by a necessary and sufficient condition on the loading which corresponds to a finite dimensional linear programming problem. In two dimensions, we show that any such web can be replaced by one in which there are at most P elementary loops, where elementary means that the loop cannot be subdivided into subloops, and where P is the number of forces f 1 ,  f 2 , …,  f N applied at points strictly within the convex hull of x 1 ,  x 2 , …,  x N . In three dimensions, we show that, by slightly perturbing f 1 ,  f 2 , …,  f N , there exists a uniloadable web supporting this loading. Uniloadable means it supports this loading and all positive multiples of it, but not any other loading. Uniloadable webs provide a mechanism for channelling stress in desired ways.

On three-dimensional printing of 17-4 precipitation-hardenable stainless steel with direct metal laser sintering in aircraft structural applications

2021 ◽  
pp. 146442072110448
Author(s):  
Rupinder Singh ◽  
Rishab ◽  
Jashanpreet S Sidhu
Keyword(s):  
Stainless Steel ◽  
Structural Engineering ◽  
Three Dimensional ◽  
Surface Hardness ◽  
Dimensional Accuracy ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Structural Components ◽  
Direct Metal Laser Sintering ◽  
Structural Applications

The martensitic 17-4 precipitation-hardenable stainless steel is one of the commercially established materials for structural engineering applications in aircrafts due to its superior mechanical and corrosion resistance properties. The mechanical processing of this alloy through a conventional manufacturing route is critical from the dimensional accuracy (Δ d) viewpoint for development of innovative structural components such as: slat tracks, wing flap tracks, etc. In past two decades, a number of studies have been reported on challenges being faced while conventional processing of 17-4 precipitation-hardenable stainless steel for maintaining uniform thickness of aircraft structural components. However, hitherto little has been reported on direct metal laser sintering of 17-4 precipitation-hardenable stainless steel for development of innovative functional prototypes with uniform surface hardness (HV), Δ d, and surface roughness ( Ra) in aircraft structural engineering. This paper reports the effect of direct metal laser sintering process parameters on HV, Δ d, and Ra for structural components. The results of study suggest that optimized settings of direct metal laser sintering from multifactor optimization viewpoint are laser power 100 W, scanning speed 1400 mm/s, and layer thickness 0.02 mm. The results have been supported with scanning electron microscopy analysis (for metallurgical changes such as porosity (%), HV, grain size, etc.) and international tolerance grades for ensuring assembly fitment.

Economical design for long-span soil – metal structures

1996 ◽  
Vol 23 (4) ◽  
pp. 838-849 ◽  
Author(s):  
Hesham Mohammed ◽  
John B. Kennedy
Keyword(s):  
Dimensional Analysis ◽  
Structural Engineering ◽  
Three Dimensional ◽  
Metal Structure ◽  
Reinforced Soil ◽  
Soil System ◽  
Metal Structures ◽  
Long Span ◽  
Economical Design ◽  
Soil Metal

Soil – metal structures consisting of metal conduits covered with soil have been used extensively for short-span bridges. Recently, some designers ventured into utilizing them for longer spans with shallow soil cover which has led to some failures. Long-span soil – metal structures are often designed with transverse stiffeners attached to the metal structure. Another approach is the use of a reinforced-soil system in which the surrounding soil is reinforced and the metal conduit is tied into the soil. In this paper, a three-dimensional analysis of long-span soil – metal structures is carried out using these two approaches. The analysis is verified and substantiated by results from laboratory models. The structural responses from the two designs show that the latter design approach leads to a more economical structure. A design example based on the Cheese Factory Bridge built in Ontario in 1984 is presented. Key words: bridges, design, long span, reinforced soil, soil – metal structures, structural engineering, three-dimensional analysis.

Design of the Purdue Experimental Turbine Aerothermal Laboratory for Optical and Surface Aero-Thermal Measurements

2016 ◽  
Author(s):  
G. Paniagua ◽  
D. Cuadrado ◽  
J. Saavedra ◽  
V. Andreoli ◽  
T. Meyer ◽  
...  
Keyword(s):  
Test Section ◽  
Structural Engineering ◽  
Optical Measurement ◽  
Pressure Ratio ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Large Mass ◽  
Modern Technology ◽  
Computational Fluid Mechanics ◽  
Test Duration

Following three decades of research in short duration facilities, Purdue University has developed an alternative turbine facility in view of the modern technology in computational fluid mechanics, structural analysis, manufacturing, heating, control and electronics. The proposed turbine facility can perform both short transients and long duration tests, suited for precise heat flux, efficiency and optical measurement techniques to advance turbine aero-thermo-structural engineering. The facility has two different test sections, linear and annular, to service both fundamental and applied research. The linear test section is completely transparent for visible spectra, aimed at TRL 1 and 2. The annular test section was designed with optical access to perform proof of concepts as well as validation of turbine components at the relevant non-dimensional parameters in small engine cores, TRL 3 to 4. The large mass flow (28 kg/s) combined with a minimum hub radius to tip radius of 0.85 allows high spatial resolution. The Reynolds (Re) number extends from 60,000 to 3,000,000, based on the vane outlet flow with an axial chord of 0.06 m and a turning angle of 72 deg. The pressure ratio can be independently adjusted, allowing for testing from low subsonic to Mach 3.2. To ensure that the thermal boundary layer is fully developed the test duration can range from milliseconds to minutes. The manuscript provides a detailed description of the sequential design methodology from zero-dimensional to three-dimensional unsteady analysis as well as of the measurement techniques available in this turbine facility.

scholarly journals ANALYSIS OF DISCRETISATION STRATEGY FOR AREA AND SPACE MEASUREMENT

2012 ◽  
Vol 31 (1) ◽  
pp. 28-31
Author(s):  
Vytautas Giniotis ◽  
Darius Mariūnas
Keyword(s):  
Structural Engineering ◽  
Three Dimensional ◽  
Geometric Accuracy ◽  
New Techniques ◽  
Volumetric Features ◽  
Geometrical Features ◽  
Dimensional Measurements ◽  
Space Measurement ◽  
Complicated Task

Measurement strategy is discussed in the article. It is important to optimise the data selection (sampling) from the object for the determination of its geometrical features within some limits of accuracy. The minimal and maximal intervals of measurement must be selected ensuring the maximal efficiency of operation and the accuracy as well. In machine engineering the typical case is in the calibration of coordinate measuring machines (CMMs) as it is a quite complicated task because of the variety of accuracy parameters to be checked and the high accuracy that must be assured. Some new techniques for the two- and three-dimensional measurements are discussed in this paper leading to a more efficient calibration process. This is relevant to machine engineering where geometric accuracy parameters are to be determined, to the geodetic measurements where slopes of terrain, area flatness and volumetric features are surveyed, in structural engineering, etc.

Engineering Establishment of Living Quarters for Jack-Up Rig Structures

2016 ◽  
Author(s):  
Yeong Su Ha ◽  
Joo Shin Park ◽  
Jeong Bon Koo ◽  
Byung Jin Cho ◽  
Kuk Yeol Ma ◽  
...  
Keyword(s):  
Structural Engineering ◽  
Three Dimensional ◽  
Technical Specification ◽  
International Standards ◽  
Structural Safety ◽  
Fe Model ◽  
Wave Loads ◽  
Offshore Structure ◽  
Local Loads ◽  
Jack Up

The Living-Quarters (hereafter referred to as ‘LQ’) is one of the major structures for ship and offshore structure. The LQ gives safe living conditions to crews on board. Until now the structural design of LQ structure is based on simplistic beam calculation to determine the initial scantling under design load. These days, safety for people is a raising issue. It is needed to meet the high oil company’s needs as well as technical specification throughout offshore project. But, the engineering procedure for LQ structure is not clearly defined by classification of society rules and international standards. In this paper, the newly engineering procedure for LQ design is established considering LQ global loads with local loads for large equipment such as helideck structure, telecom mast and life saving appliances, and so on. To consider LQ global loads with local loads, the integrated three dimensional FE model and high technology engineering should be needed to require many kind of rules for equipment. Recently, the damage of LQ structure is occasionally reported during towing condition for jack-up rig structure. The LQ of jack-up rig is encountered such as slamming pressure and greenwater produced by harsh wave loads during towing condition because of small height of freeboard comparing to the wave height. To verify the structural safety under towing condition, the detailed non-liner analysis is performed to verify the load-carrying capacity against greenwater pressure. We newly propose a structural engineering procedure to improve the reliability of the LQ design in the jack-up rigs. From basis of this procedure, a more reasonable and optimized results are proposed as a practical manner as well as scientific approach.

The Influence of Long-Range Residual Stress on Plastic Collapse and Local Yielding of Internally Pressurized Pipes

2012 ◽  
Author(s):  
Gui-yi Wu ◽  
D. J. Smith ◽  
M. J. Pavier
Keyword(s):  
Residual Stresses ◽  
Long Range ◽  
Structural Engineering ◽  
Three Dimensional ◽  
Plastic Collapse ◽  
Displacement Control ◽  
Integrity Assessment ◽  
End Conditions ◽  
Global Collapse ◽  
Local Yielding

The determination of plastic collapse for cracked pipes is important in structural engineering design and component integrity assessment. Long-range residual stresses are usually treated as primary stresses which contribute to plastic collapse of pipes subjected to internal pressure. This paper explores the differences between load and displacement controlled conditions applied to the ends of thin- and thick-walled pipes. Both load and displacement control can represent long range or fit-up residual stresses if they are considered as primary or secondary stresses respectively. Both global collapse and local yielding for pipes containing partially and fully circumferential cracks are examined. Detailed three-dimensional (3D) finite element (FE) analyses are used to simulate the pipe and crack geometry and the boundary conditions. The cracked pipes are assumed to be open ended. For a defect free pipe the FE results for global collapse agree with analytical solutions for both load and displacement controlled end conditions. For high tensile end loads and displacements lower collapse pressures are found for displacement conditions, while it is the converse for high compressive end loading. However, when a crack is introduced it becomes evident that tensile or compressive displacement control has little impact on global collapse and therefore longrange displacement controlled (or residual) stresses do not contribute to collapse. On the other hand local net section yielding is strongly affected by either load or displacement controlled end conditions.

scholarly journals Modelling and Simulation of Compression Behaviour of 3D Woven Hollow Composite Structures Using FEM Analysis

2020 ◽  
Vol 3 (1) ◽  
pp. 6-18
Author(s):  
Lekhani Tripathi ◽  
Soumya Chowdhury ◽  
Bijoya Kumar Behera
Keyword(s):  
Composite Structures ◽  
Structural Engineering ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Compression Behaviour ◽  
Opposite Trend ◽  
Superior Mechanical Properties ◽  
Cross Links ◽  
Spacer Fabrics ◽  
Good Agreement

Three-dimensional (3D) woven spacer composites have the advantage of being lightweight and strong for use in various segments of structural engineering and automobiles due to their superior mechanical properties than conventional counterparts. In this investigation, the influence of different cell geometries of 3D woven spacer fabrics, namely rectangular, triangular and trapezoidal with woven cross-links, upon their mechanical behaviors, especially compression energy, was studied through FEM (finite element method). Cell geometries were changed into different heights and widths and evaluated through simulation and experiments. Simulation of the structure was carried out by the Abaqus platform, and validation of the results was done for the rectangular structure. It was found that compression energy increases with an increment in width, while initially, it shows the tendency to increase and subsequently decrease with an increment in height for the rectangular structure. Compression energy increases with an increase in the angle of the triangular structure; however, it shows the opposite trend in the case of the trapezoidal structure. The outcome of the result shows good agreement between simulation and experimentation values of more than 94% accuracy.

Design of the Purdue Experimental Turbine Aerothermal Laboratory for Optical and Surface Aerothermal Measurements

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
G. Paniagua ◽  
D. Cuadrado ◽  
J. Saavedra ◽  
V. Andreoli ◽  
T. Meyer ◽  
...  
Keyword(s):  
Test Section ◽  
Structural Engineering ◽  
Optical Measurement ◽  
Pressure Ratio ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Large Mass ◽  
Modern Technology ◽  
Computational Fluid Mechanics ◽  
Imaging And Spectroscopy

Following three decades of research in short duration facilities, Purdue University has developed an alternative turbine facility in view of the modern technology in computational fluid mechanics, structural analysis, manufacturing, heating, control, and electronics. The proposed turbine facility can operate continuously and also perform transients, suited for precise heat flux, efficiency, and optical measurement techniques to advance turbine aerothermo-structural engineering. The facility has two different test sections, linear and annular, to service both fundamental and applied research. The linear test section is completely transparent for optical imaging and spectroscopy, aimed at technology readiness levels (TRLs) of 1–2. The annular test section was designed with optical access to perform proof of concepts as well as validation of turbine component performance for relevant nondimensional parameters at TRLs of 3–4. The large mass flow rate (28 kg/s) combined with a minimum hub to tip ratio of 0.85 allows high spatial resolution. The Reynolds number (Re) extends from 60,000 to 3,000,000, based on the vane outlet flow properties with an axial chord of 0.06 m and a turning angle of 72 deg. The pressure ratio can be independently adjusted, enabling testing from low subsonic to Mach 3.2. This paper provides a detailed description of the sequential design methodology from zero-dimensional to three-dimensional (3D) unsteady analysis as well as of the measurement techniques available in this turbine facility.

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