Shape Optimization of Isotropic Composite Beams Undergoing Harmonic Flexural and Torsional Loading

1999 ◽  
Author(s):  
Arnold Lumsdaine ◽  
Arnoldo Garcia ◽  
Ying Yao
Keyword(s):  
Cross Sections ◽  
Steel Structure ◽  
Acrylonitrile Butadiene Styrene ◽  
Composite Beams ◽  
Harmonic Excitation ◽  
Intermediate Mass ◽  
Cross Sectional ◽  
Isotropic Composite ◽  
Design Variables ◽  
Inertial Component

Abstract The purpose of this study is to optimize beams undergoing harmonic excitation in both bending and torsion due to an intermediate mass and inertial component. The objective is to minimize the weight for a composite beam made of glass reinforced acrylonitrile butadiene styrene (ABS), while maintaining performance above a given natural frequency. Design variables are the cross-sectional dimensions. Weight reduction is computed compared to a uniform case. The results are obtained for two different composites with different glass densities, and compared with results obtained with a steel structure. The structure examined is a clamped-clamped beam with an intermediate mass and inertial component. Basic structures are modeled and optimized analytically. Coupling effects are modeled discretely using finite elements, and these structures are optimized using commercial software. Structures with closed (circular) and open (channel) cross-sections are examined. Results show order of magnitude improvement of optimized structures for both steel and composite beams.

scholarly journals Mechanical Behavior of Damaged H-Section Steel Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xibing Hu ◽  
Rui Chen ◽  
Yuxuan Xiang ◽  
Yafang Chen ◽  
Qingshan Li
Keyword(s):  
Cross Sections ◽  
Elastic Moduli ◽  
Mechanical Test ◽  
Steel Structure ◽  
Steel Structures ◽  
Computational Accuracy ◽  
Cross Sectional ◽  
Steel Columns ◽  
Steel Members ◽  
The Cross

Steel structures are usually damaged by disasters. According to the influence law of the damage on the elastic modulus of steel obtained by the mechanical test of damaged steel, the average elastic moduli of H-section steel members were analyzed. The equations for calculating the average elastic moduli of damaged H-section steel members at different damage degrees were obtained. By using the analytical cross-sectional method, the cross-sectional M-Φ-P relationships and the dimensionless parameter equations of the H-sections in the full-sectional elastic distribution, single-sided plastic distribution, and double-sided plastic distribution were derived. On the basis of the cross-sectional M-Φ-P relationships and dimensionless parameters of actual steel members, the approximate calculation equations for the damaged cross sections were obtained. The Newmark method was used to analyze the deformation of damaged steel columns. Analytical results show good agreement with the test results. The equations and methods proposed in this study have high computational accuracy, and these can be applied to the cross-sectional M-Φ-P relationships and deformation calculation of damaged steel members.

Cross Section Optimization of Plane Truss among Different Spans

2014 ◽  
Vol 679 ◽  
pp. 1-5 ◽  
Author(s):  
Sumayah Abdulsalam Mustafa ◽  
Mohd Zulham Affandi bin Mohd Zahid ◽  
Md.Hadli bin Abu Hassan
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Element Analysis ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Cross Section Shape ◽  
Design Variables ◽  
Section Shape ◽  
Steel Sections ◽  
Research Show

Cross sectional areas optimization is to be implemented to study the influence of the cross section shape on the optimum truss weight. By the aid of analysis and design engines with advanced finite element analysis that is the steel design software STAAD. Four rolled steel sections (angle, tube, channel, and pipe) which are used in industrial roof trusses are applied for comparison. Many previous studies, use the areas of cross sections as design variables without highlight to the shape of cross section at the start of the process, consequently the result area will be adequate if the designer choose the effective shape than others. Results of this research show that the chosen cross section shape has a significant impact on the optimum truss weight for same geometry of truss type under the same circumstances of loading and supports.

Study on the Optimal Design of the Members of Contaniner Building with Building Materials I: Side Board Optimization

2013 ◽  
Vol 859 ◽  
pp. 270-273 ◽  
Author(s):  
Xiao Xiong Zha ◽  
Yang Zuo ◽  
Shi Yun Chen
Keyword(s):  
Software Package ◽  
Design Theory ◽  
Optimization Design ◽  
Building Materials ◽  
Steel Structure ◽  
Building Construction ◽  
Cross Sectional ◽  
Design Variables ◽  
Cross Sectional Dimension ◽  
Cross Sectional Size

Container, as a light steel structure, being increasingly used in building construction, containers used in construction has many advantages and applications. However, the current study mostly from the view of the architecture, as for the mechanical properties of the container building has not mentioned, that brings obstacles of the application and development of the container building. Based on the software package of HyperWorks and optimization design theory, the cross-sectional size of container building is taken as design variables, and then selected objective function and constraint functions. Finally, calculated by software, get the optimal cross-sectional dimension.

Nonclassical Behavior of Thin‐Walled Composite Beams with Closed Cross Sections

1990 ◽  
Vol 35 (2) ◽  
pp. 42-50 ◽  
Author(s):  
Lawrence W. Rehfield ◽  
Ali R. Atilgan ◽  
Dewey H. Hodges
Keyword(s):  
Cross Sections ◽  
Transverse Shear ◽  
Composite Beams ◽  
Cross Sectional ◽  
Elastic Bending ◽  
Composite Blade ◽  
Beam Displacement ◽  
Thin Walled ◽  
Cantilevered Beams ◽  
Shear Coupling

This paper focuses on two nonclassical effects in the behavior of thin‐walled composite beams: elastic bending‐shear coupling and restrained torsional warping. These nonclassical effects are clarified and analyzed in some simple examples involving cantilevered beams. First, elastic bending‐transverse shear coupling is shown to be important in the analysis of beams designed for extension‐twist coupling. It is found that the lateral deflections ran be off by more than a factor of two if this coupling is ignored. This coupling stems from plies with off‐axis fibers in the beam. The presence of these plies affects significantly the modeling approach (i.e., determination of the constitutive equations) in that transverse shear must appear in the kinematics so that its coupling with bending will he exhibited in the elastic constants. This finding is in accord with “exact” beam theories which develop the beam displacement and cross sectional orientation in terms of six kinematical variables instead of the three or four found in some previously published works on composite blade modeling. A second nonclassical effect, torsional warping rigidity, is shown to be important far certain box beams having a thin‐walled, closed cross section. The importance of including these nonclassical phenomena in a complete theory is discussed in light of the magnitude of their effects for various values of configuration parameters.

scholarly journals Optimum Robot Design Based on Task Specifications Using Evolutionary Techniques and Kinematic, Dynamic, and Structural Constraints

2002 ◽  
Author(s):  
P. S. Shiakolas ◽  
D. Koladiya ◽  
J. Kebrle
Keyword(s):  
Genetic Algorithms ◽  
Differential Evolution ◽  
Cross Sections ◽  
Evolutionary Optimization ◽  
Robot Design ◽  
Structural Constraints ◽  
Link Length ◽  
Cross Sectional ◽  
Physical Constraints ◽  
Design Variables

In this paper, we discuss optimum robot design based on task specifications using evolutionary optimization approaches. The three evolutionary optimization approaches employed are Simple Genetic Algorithms, Genetic Algorithms with elitism, and Differential Evolution. These approaches were used for the optimum design of SCARA and articulated type manipulators. The objective function minimizes the torque required for the motion subject to deflection and physical constraints with the design variables being the physical characteristics of link (length and cross sectional area parameters). In this work, we experimented links with various cross sections. The main findings of this research are that the differential evolution converges quickly, requires significantly less number of iterations and achieves better results.

Bending and Extension of Thin-Walled Composite Beams of Open Cross-Sectional Geometry

2000 ◽  
Vol 67 (4) ◽  
pp. 813-818 ◽  
Author(s):  
O. Rand
Keyword(s):  
Theoretical Model ◽  
Cross Sections ◽  
Composite Beams ◽  
Cross Sectional ◽  
Out Of Plane ◽  
Thin Walled ◽  
Similarities And Differences ◽  
Coupling Mechanisms

A theoretical model for bending and extension of composite beams of open thin-walled geometry is devised. The model is based on a detailed description of the out-of-plane warping and may handle generic open cross-sectional geometries and arbitrary layup configurations. In view of the potential of composite beams to produce useful structural couplings, the analysis is focused on the ability to predict the coupling mechanisms, and draw lines of similarities and differences between such beams and similar thin-walled beams of closed cross sections. [S0021-8936(00)01204-6]

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 Bonding widths of Deposited Polymer Strands in Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 871
Author(s):  
Cheng Luo ◽  
Manjarik Mrinal ◽  
Xiang Wang ◽  
Ye Hong
Keyword(s):  
Polymer Melt ◽  
Acrylonitrile Butadiene Styrene ◽  
High Viscosity ◽  
Numerical Results ◽  
Fused Filament Fabrication ◽  
Cross Sectional ◽  
Nozzle Height ◽  
Special Cases ◽  
Cross Sectional Profile ◽  
Sectional Profile

In this study, we explore the deformation of a polymer extrudate upon the deposition on a build platform, to determine the bonding widths between stacked strands in fused-filament fabrication. The considered polymer melt has an extremely high viscosity, which dominates in its deformation. Mainly considering the viscous effect, we derive analytical expressions of the flat width, compressed depth, bonding width and cross-sectional profile of the filament in four special cases, which have different combinations of extrusion speed, print speed and nozzle height. We further validate the derived relations, using our experimental results on acrylonitrile butadiene styrene (ABS), as well as existing experimental and numerical results on ABS and polylactic acid (PLA). Compared with existing theoretical and numerical results, our derived analytic relations are simple, which need less calculations. They can be used to quickly predict the geometries of the deposited strands, including the bonding widths.

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