Numerical Analysis of a Rigid Node of a Spatial Timber Frame Made of Structural Elements with Built-up Cross-Sections

2013 ◽  
Vol 778 ◽  
pp. 639-646 ◽  
Author(s):  
Cristina E. Lanivschi ◽  
Alexandru Secu ◽  
Gabriela M. Atanasiu
Keyword(s):  
Numerical Analysis ◽  
Finite Elements ◽  
Elastic Properties ◽  
Design Process ◽  
Cross Sections ◽  
Structural Elements ◽  
Cross Sectional ◽  
Timber Frame ◽  
One Step ◽  
Internal Forces

Considering wood currently used in construction domain, it may be observed that it possesses good strengths, but reduced modules of elasticity. This drawback may be prevented by creating structures with rigid nodes or by using hybrid or composed cross-sections for the structural elements.The paper consists of numerical analysis of a timber frame with rigid nodes, assuming composed cross-sections for the structural elements, made of four props with cross-sectional dimensions of 0.1x0.1 m each - for columns and two chords of 0.1x0.1 m each - for beams.Analyzing this type of structures by considering equivalent cross sections` properties of the structural elements, the real phenomena may not be covered, since it doesn`t consider all elastic characteristics of wood, resulting in different stress` distribution in the structural elements.The analyze of this structure considering both real solid cross-sections and all elastic properties of wood by using specialized software, leads to a laborious work because of the high number of finite elements. Thereby, a two-step analysis is proposed: the first one consists in solving the spatial timber frame with bar type finite elements and the elastic properties parallel to the grain, as provided by design codes. In the second step, an intermediary node is detached and loaded with the internal forces obtained from the first step, considering all elastic parameters of wood and using solid type finite elements.Currently, in the design process, only the first step in performed. The two-step analysis aims to compare the results with those obtained using the strength of materials methods, relieving the necessary corrections in the case of one-step design process.

Effects of a Bolster Curvature on an Automobile Seat Fit

2021 ◽  
Vol 65 (1) ◽  
pp. 423-426
Author(s):  
Baekhee Lee ◽  
Byoung-Keon (Daniel) Park ◽  
Kihyo Jung ◽  
Jangwoon Park
Keyword(s):  
Logistic Regression ◽  
Design Process ◽  
Cross Sections ◽  
Classification Accuracy ◽  
Regression Method ◽  
Digital Design ◽  
Cross Sectional ◽  
Development Costs ◽  
Logistic Regression Method ◽  
Vehicle Seat

Vehicle-seat dimensions measured at specific cross-sections have been historically utilized as shape determinants to evaluate a driver’s seat fit. The present study is intended to quantify the relationships between seat fits and the seat dimensions for designing an ergonomic vehicle seat. Eight seat engineers evaluated seat fits for 54 different driver seats based on their expertise. Five seat dimensions were measured at six cross-sectional planes using a custom-built, computerized program. The best-subset-logistic-regression method was employed to model the relationships between the seat fit and the seat dimensions. As a result, significant seat dimensions, such as insert width, bolster height, and/or bolster curvature, on the subjective seat fit (e.g., loose-fit, right-fit, and tight-fit) were quantified. The developed models showed 98% overall classification accuracy throughout the cross-sectional planes. The models promote a digital design process of an automobile seat, which would increase the efficiency of the process and reduce the development costs.

Construction and Application of 3D and 2D Type Maps for Linkages

2012 ◽  
Vol 433-440 ◽  
pp. 2377-2386
Author(s):  
Wen Yeuan Chung
Keyword(s):  
Numerical Analysis ◽  
Design Process ◽  
Cross Sections ◽  
Three Dimensional ◽  
Solid Modeling ◽  
3D Models ◽  
Output Link ◽  
Different Types ◽  
Modeling Software ◽  
Drag Link

The 3D and 2D type maps for planar four-bar and simply RSSR linkages are constructed with illustration of their application. The criteria determining the rotatability of input or output link are developed or reviewed for both linkages. Three-dimensional type maps are then constructed by integrating the tool for numerical analysis and solid modeling software, e.g. MATLAB and PRO/E. The coordinate axes are mainly three ratios of link lengths. The types are classified based on whether the input or output link can make fully rotation. Each type map is composed of five regions representing different types. They are drag link, crank-rocker, rocker-crank, double-rocker, and unassembled. Any cross sections can be taken readily and arbitrarily from the 3D models along any plane or surfaces to get 2D type maps. The constructed type maps are also combined with curves or surfaces representing performances of transmission ratio. With type maps and related surfaces, the design process can be simplified and expedited substantially.

scholarly journals Comparison of Internal Forces Redistribution and Displacements Subjected to the Dynamic Wind Gusts depending of Point Fixed Glass Connector Model Shape

2021 ◽  
Author(s):  
Krzysztof Kuliński ◽  
Przemysław Palacz
Keyword(s):  
Numerical Analysis ◽  
Cross Sections ◽  
Numerical Models ◽  
Glass Plate ◽  
Wind Pressure ◽  
The Finite Element Method ◽  
Wind Gusts ◽  
Maximum Value ◽  
Internal Forces ◽  
Different Shapes

This paper presents an analysis of the redistribution of stresses and displacements in numerical models of various shapes of glass connectors. Two states of dynamic wind gusts were analyzed: the maximum value of suction and the maximum value of wind pressure. For the sake of simplicity, wind gusts were assumed periodically as a sinusoidal function. The model adopts a rectangular glass plate that transmits wind pressure and suction through the point fixed glass connectors. Therefore, single-arm cross connectors were not only subjected to bending stress, but also to torsion. Four different shapes of connectors were analyzed. In the first part of the numerical analysis, T-shaped and C-shaped cross-sections were adopted, and in the next part, both connectors were modified by adding fillet welds to the models. The dynamic numerical analysis was performed using the finite element method in the ADINA program.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

Automated 3D measurement of fiber cross section morphology in handsheets

2012 ◽  
Vol 27 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Christian Lorbach ◽  
Ulrich Hirn ◽  
Johannes Kritzinger ◽  
Wolfgang Bauer
Keyword(s):  
Image Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Image Plane ◽  
3D Measurement ◽  
Cross Sectional ◽  
Fiber Cross Section ◽  
Fiber Wall ◽  
Sectional Shape ◽  
Cross Section Geometry

Abstract We present a method for 3D measurement of fiber cross sectional morphology from handsheets. An automated procedure is used to acquire 3D datasets of fiber cross sectional images using an automated microtome and light microscopy. The fiber cross section geometry is extracted using digital image analysis. Simple sample preparation and highly automated image acquisition and image analysis are providing an efficient tool to analyze large samples. It is demonstrated that if fibers are tilted towards the image plane the images of fiber cross sections are always larger than the true fiber cross section geometry. In our analysis the tilting angles of the fibers to the image plane are measured. The resulting fiber cross sectional images are distorted to compensate the error due to fiber tilt, restoring the true fiber cross sectional shape. We use an approximated correction, the paper provides error estimates of the approximation. Measurement results for fiber wall thickness, fiber coarseness and fiber collapse are presented for one hardwood and one softwood pulp.

scholarly journals Thermo-Hydraulic Performance of U-Tube Borehole Heat Exchanger with Different Cross-Sections

2021 ◽  
Vol 13 (6) ◽  
pp. 3255
Author(s):  
Aizhao Zhou ◽  
Xianwen Huang ◽  
Wei Wang ◽  
Pengming Jiang ◽  
Xinwei Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Heat Resistance ◽  
Cross Sections ◽  
Three Dimensional ◽  
Thermal Response ◽  
Transfer Efficiency ◽  
Cross Sectional ◽  
Heat Transfer Efficiency ◽  
Oval Tube

For reducing the initial GSHP investment, the heat transfer efficiency of the borehole heat exchange (BHE) system can be enhanced to reduce the number or depth of drilling. This paper proposes a novel and simple BHE design by changing the cross-sectional shape of the U-tube to increase the heat transfer efficiency of BHEs. Specifically, in this study, we (1) verified the reliability of the three-dimensional numerical model based on the thermal response test (TRT) and (2) compared the inlet and outlet temperatures of the different U-tubes at 48 h under the premise of constant leg distance and fluid area. Referent to the circular tube, the increases in the heat exchange efficiencies of the curved oval tube, flat oval tube, semicircle tube, and sector tube were 13.0%, 19.1%, 9.4%, and 14.8%, respectively. (3) The heat flux heterogeneity of the tubes on the inlet and outlet sides of the BHE, in decreasing order, is flat oval, semicircle, curved oval, sector, and circle shapes. (4) The temperature heterogeneity of the borehole wall in the BHE in decreasing order is circle, sector, curved oval, flat oval, and semicircle shapes. (5) Under the premise of maximum leg distance, referent to the heat resistance of the tube with a circle shape at 48 h, the heat exchange efficiency of the curved oval, flat oval, semicircle, and sector tubes increased 12.6%, 17.7%, 10.3%, and 7.8%, respectively. (6) We found that the adjustments of the leg distance and the tube shape affect the heat resistance by about 25% and 12%, respectively. (7) The flat-oval-shaped tube at the maximum leg distance was found to be the best tube design for BHEs.

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

2010 ◽  
Vol 638-642 ◽  
pp. 675-680 ◽  
Author(s):  
Martina Thomann ◽  
Nina von der Höh ◽  
Dirk Bormann ◽  
Dina Rittershaus ◽  
C. Krause ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Degradation Process ◽  
Cross Sectional Area ◽  
Bending Test ◽  
Sectional Area ◽  
Cross Sectional ◽  
Initial Strength ◽  
Three Point Bending ◽  
The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

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