Reliability Evaluation of Double-Layer Spherical Lattice Shell

2013 ◽  
Vol 405-408 ◽  
pp. 905-908
Author(s):  
Hui Jun Li ◽  
Zheng Zhong Wang
Keyword(s):  
Yield Strength ◽  
Double Layer ◽  
Random Variables ◽  
Sectional Area ◽  
Cross Sectional ◽  
Different Types ◽  
Calculated Effect ◽  
Lattice Shell ◽  
External Loads ◽  
Lattice Shells

Reliability and sensitivity of double-layer spherical lattice shells are extensively investigated, moreover the effect of different types of random variables and different positions of random variables on reliability and sensitivity are also studied in detail. External loads, cross-sectional area and yield strength of members are defined as random variables respectively according to their types and layouts in the lattice shells, and their effects on sensitivity are substantially calculated. Effect of random variables on several performance functions is also studied. Finally, correlations among these performance functions are calculated.

True Cross Sectional Area of Screw Threads With Helix and Root Radius Geometries Taken Into Consideration

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Toshimichi Fukuoka ◽  
Masataka Nomura
Keyword(s):  
Cross Sectional Area ◽  
Equivalent Diameter ◽  
Sectional Area ◽  
Algebraic Equations ◽  
Root Radius ◽  
Cross Sectional ◽  
Threaded Fasteners ◽  
Fine Pitch ◽  
Screw Threads ◽  
External Loads

When evaluating the strength of threaded fasteners under external loads, stress area is commonly used. However, in order to elucidate the mechanical behavior of bolted joints more rigorously and extensively, it is desired to derive an analytical expression of the true cross sectional area of screw threads, with the effects of the helix and root radius taken into account. In this paper, a series of closed-form algebraic equations, which can calculate true cross sectional areas of internal and external screw threads, is derived. The equations obtained can be applied to both metric and inch screw threads with a coarse or a fine pitch. Then, the equivalent diameter of the true sectional area is defined and compared with the pitch diameter and stress area diameter.

Tensile Properties of Different Silkworm Silk Fibers

2008 ◽  
Vol 47-50 ◽  
pp. 1213-1216 ◽  
Author(s):  
Hoi Yan Cheung ◽  
Kin Tak Lau ◽  
Yong Qing Zhao ◽  
Jian Lu
Keyword(s):  
Electron Microscopy ◽  
Bombyx Mori ◽  
Sectional Area ◽  
Cross Sectional ◽  
Elongation At Break ◽  
Silk Fibers ◽  
Different Types ◽  
Strain Data ◽  
Silkworm Silk ◽  
Scanning Electron

Mechanical properties of two different types of silkworm silk fibers under three conditions: (i) Bombyx mori; (ii) twisted Bombyx mori; and (iii) Tussah silk fibers were under investigations. The values of ultimate tensile strength, elongation at break and Young’s modulus were examined by performing tensile test on single bave. Scanning electron microscopy (SEM) was used to observe the morphologies of the two different types of silk fibers, and measure their general diameters so as to determine the cross-sectional area of the two different types of silk fibers and convert the experimental load-extension data into stress-strain data accordingly.

Thermal performance of six different types of wavy-fins

2015 ◽  
Vol 25 (4) ◽  
pp. 892-911 ◽  
Author(s):  
AbdulRahim Assaad Khaled
Keyword(s):  
Heat Transfer ◽  
Surface Wave ◽  
Cross Sectional Area ◽  
Wavy Surface ◽  
Wave Frequency ◽  
Sectional Area ◽  
Cross Sectional ◽  
Small Surface ◽  
Content Type ◽  
Different Types

Purpose – Heat transfer inside wavy fins is analyzed in this work. The paper aim to discuss this issue. Design/methodology/approach – Six different types of wavy fins are considered. The fin equation for each fin type is solved using a high accurate finite difference method. Excellent agreement is obtained between the numerical solution under zero wave amplitude and the exact solution of the plain fin. Findings – The following wavy fin types and conditions are found to produce larger heat transfer rate and its volumetric value than those for the plain fin and other wavy fins: short fins with parallel wavy profiles and large surface-wave frequency; long fins with symmetric wavy surface around the length axis, positive cross-sectional area gradient at the base, and large surface-wave frequency; and long fins with symmetric wavy profiles around the length axis, positive cross-sectional area gradient at the base, and small surface-wave frequency. Research limitations/implications – In addition, both fins with symmetric wavy surface around the width axis and parallel wavy surfaces along the width axis have same performance indicators. Also, these wavy fins possess higher fin efficiency than either that of the plain fin or those of the other types of wavy fins. Originality/value – Finally, heat transfer enhancements in the studied wavy fins are increased by increases in the excess of the surface area, cross-sectional area gradient at the base, arc length and arc width relative to those of the plain fin.

scholarly journals Structural performance of frames with concrete-filled steel tubular columns and steel beams: Finite element approach

2019 ◽  
Vol 28 ◽  
pp. 2633366X1989459
Author(s):  
Ahmed Dalaf Ahmed ◽  
Esra Mete Güneyisi
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Simulation Models ◽  
Steel Tube ◽  
Nonlinear Material ◽  
Steel Beams ◽  
Sectional Area ◽  
Cross Sectional

Composite columns such as concrete-filled steel tube (CFST) were adopted in many building constructions in recent years because of carrying high loading with the ability to resist buckling and small cross-sectional area. The high behavior of the CFST columns is due to the interaction between steel and concrete which called the composite action. This type of composite column without main and tie reinforcements embedded in concrete gives high axial compression strength to resist the external loadings with the economic sectional area. The work presented in this article includes simulation models that tested by other researchers and a parametric study on the performance of frames that connected steel beam by composed columns of circular CFST that subjected to lateral loading. A finite element (FE) approach is adopted to simulate the models by ANSYS software. All models consider the linear and nonlinear material analysis of the concrete and steel. The validity of the developed model was examined by comparing with the experimental data founded in the literature. Different parameters such as the ratio of the axial load, the slenderness ratio of CFST column, the linear stiffness ratio of the beam–column, the steel yield strength of the beam, the steel yield strength of the tube, and concrete strength on the performance of the composite frames were also studied and the load-deformation performance was obtained over the different cases of the study. Analysis results by FE modeling were in good agreement with the experimental results.

scholarly journals Influence of Imperfections on Behaviour of Thin-walled Steel-concrete Composite Columns

Mechanika ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 5-11
Author(s):  
Deividas MARTINAVIČIUS ◽  
Mindaugas AUGONIS
Keyword(s):  
Concrete Columns ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Composite Columns ◽  
Area Reduction ◽  
Buckling Stress ◽  
Geometrical Imperfection ◽  
Different Types

This paper presents experimental and numerical analysis of the composite steel-concrete columns. Three columns are tested experimentally. Overall forty-eight FE models are created. Sixteen different models for every experimental column are analysed to evaluate the influence of the different types of imperfections. It was found that the imperfections reduced the resistance of the composite columns by up to 10 %. Limiting the geometrical imperfection amplitudes to B/200, the steel profile effective cross-sectional area reduction by up to 23 % was observed, while the critical buckling stress was reduced by up to 74 %. Expressions for the calculation of the effective cross-sectional area ratio and critical buckling stress are proposed.

scholarly journals ASSESSMENT OF THE OF THE ROLL - PICKER WITH COMPETITIVENESS BEATTER - BLADE GRINDING UNIT

2019 ◽  
pp. 30-42
Author(s):  
Oleksandr Kholodyuk ◽  
Anatoliy Spirin ◽  
Iryna Kovaliova
Keyword(s):  
Structural Features ◽  
Optimization Criterion ◽  
Specific Work ◽  
Sectional Area ◽  
Technological Parameters ◽  
Cross Sectional ◽  
Maximum Value ◽  
Different Types ◽  
Cutting Operation

Preparation of different stem forages is a guarantee of balanced feeding of cattle with steady maintenance. The promising technology of harvesting stalk feed, which allows you to save in the selected mass of the most valuable fractions - leaves, buds and inflorescences, is the use in the technological process of press-pickers or pickup trucks-conveyors, which contain a beatter – blade grinding unit with active disk blades. The milling of the leaf mass is one of the most energy-intensive operations in the overall process of harvesting, which also depends on the final quality of the resulting feed. The shredder is the main working unit of the feed assembly, which defines its technological scheme and the location of the main units. The main structural features of different types of crushers are considered, namely: drum, disk, rotary and multi-plane cutting, with their disadvantages and advantages in the process of work. The purpose of the article is to evaluate the various forage harvesting units in the production of haymaking on competitiveness by comparing their technical and operational indicators. The design and principle of the proposed beatter - blade grinding unit is described. The main factors influencing the process of cutting the grass mass are established. The regression equation describing the change in the specific cutting operation is given, depending on the structural and technological parameters, in particular on the sectional area of the cut mass and its moisture content. It has been established that the size of the cross-sectional area of the material most influences the optimization criterion. At humidity of alfalfa 45-55% the specific work of cutting with increasing feed is constantly decreasing, respectively, from 23,6-19,6 kJ/m2 to 6,37-4,10 kJ/m2. The methodology for evaluating the competitiveness of technical means for the harvesting of cut alfalfa with simultaneous grinding on the dimensionless and generalized indicators of the 1st and 2nd species is described. It was found that the maximum value of the generalizing index of the first species is 0.6997, and for the II-th - 3.7960 and corresponds to the prototype PV-6, which is equipped with a multi-flat cutter.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

Sign in / Sign up

Export Citation Format

Share Document