On the Determination of the Centers of Twist and of Shear for Cylindrical Shell Beams

1972 ◽  
Vol 39 (4) ◽  
pp. 1098-1102 ◽  
Author(s):  
E. Reissner ◽  
W. T. Tsai
Keyword(s):  
Cylindrical Shell ◽  
Cross Section ◽  
Flat Plates ◽  
Influence Coefficients ◽  
Special Cases ◽  
Box Beams ◽  
Circular Cylindrical Shells ◽  
Definition Of ◽  
Open Cross Section

We consider the problem on the basis of a definition of the centers of shear and of twist in terms of influence coefficients for end-loaded cantilever beams. We determine the influence coefficients approximately by combining the Saint Venant torsion and flexure solutions with an appropriate version of the principle of minimum complementary energy. We apply this method, considering the beam as a cylindrical shell. We find among other things a formula for closed-cross-section shells which includes as special cases the strength-of-materials formula for open-cross-section shells, as well as a formula for variable-thickness flat plates. Problems of particular theoretical interest for which solutions are given concern rectangular box beams and circular cylindrical shells with circumferentially varying properties.

Geometric Indicators of Flexible Slice Lip

2015 ◽  
Vol 816 ◽  
pp. 188-194
Author(s):  
Krzysztof Talaśka ◽  
Ireneusz Malujda ◽  
Dominik Wilczyński ◽  
Jan Górecki ◽  
Paweł Tarkowski ◽  
...  
Keyword(s):  
Stress State ◽  
Cross Section ◽  
External Factors ◽  
Geometric Parameters ◽  
Geometric Features ◽  
Maximum Deflection ◽  
Paper Making ◽  
Definition Of ◽  
High Flexibility

The paper is thematically connected with paper making machines. This type of the machine is equipped with a head which has a flexible slice lip for skimming the pulp applied to produce the paper. The definition of geometric features of the slice lip is a key issue. The slice lip should be made of material which is resistant to external factors, and designers want to obtain a high flexibility of this element. It is possible to get a high flexibility by forming a proper shape of the slice lip. The paper presents the proposal of dimensionless geometric indicators which combine basic geometric parameters of the slice lip. These indicators are the following: indicator of the cross-section, indicator of the length and indicator of the length of the transverse notch. FEM strength analyses were done – the aim of these analyses was the determination of the stress state and maximum deflection of the slice lip. The authors have analysed the slice lip with holes for mounting the actuators and the slice lip and with transverse notches for increasing its flexibility. The results were presented in the form of graphs.

scholarly journals Estimation of the residual resource of wooden structures by changing geometric parameters of the cross-section

2021 ◽  
Vol 244 ◽  
pp. 04010
Author(s):  
Dmitry Korolkov ◽  
Marina Gravit ◽  
Maxim Aleksandrovskiy
Keyword(s):  
Service Life ◽  
General Formula ◽  
Cross Section ◽  
Axial Force ◽  
Rate Of Change ◽  
Geometric Parameters ◽  
Advantages And Disadvantages ◽  
Special Cases ◽  
Wooden Structures

In this article, the authors propose a method for assessing the residual resource by changing the geometric parameters of wooden structures. A general formula for estimating the maximum service life is presented. Then a number of special cases are considered when calculating the ultimate service life for the first group of limiting states. As a result, formulas were derived for calculating the ultimate service life for various design cases: centrally tensioned, centrally compressed, bending members, members subject to an axial force with bending. The author considered the determination of the rate of change in geometric parameters at the macrolevel (visually observed changes) and microscopic (microcracks, breaks of bonds between atoms). Formulas for determining the rate of change of geometric parameters at the macro and micro levels are proposed. The advantages and disadvantages of this method are presented. The scope of its application is indicated.

scholarly journals Estimation of the residual resource of wooden structures by the changes of the cross section geometric parameters

2021 ◽  
Vol 18 (2) ◽  
pp. 49-56
Author(s):  
D. I. Korolkov ◽  
Keyword(s):  
General Formula ◽  
Cross Section ◽  
Rate Of Change ◽  
Geometric Parameters ◽  
Advantages And Disadvantages ◽  
Micro Cracks ◽  
Special Cases ◽  
Micro Level ◽  
Wooden Structures

In this article, the author proposes a method for assessing the residual resource of wooden structures by changes taking place in their geometric parameters. A general formula for estimating the service limit of the wooden structures is presented. Then, a number of special cases are considered when calculating the service limit for the first group of limiting states. As a result, formulas have been derived for calculating the service limit for various design cases, namely, centrally tensioned, centrally compressed members, members under bending, members subjected to the axial force with bending. The author considers the determination of the rate of geometric parameters change at the macro-level (visually observed changes) and micro-level (micro-cracks, breaks of bonds between atoms). Formulas for determining the rate of change of geometric parameters at the macro and micro levels are proposed. The advantages and disadvantages of this method are highlighted, and the scope of its application is indicated.

scholarly journals Straightening of low-rigid cylindrical details. Part I. Justification of the type of loading and modes at transverse straightening

2019 ◽  
Vol 62 (7) ◽  
pp. 517-524 ◽  
Author(s):  
S. A. Zaides ◽  
Kuang Le Khong
Keyword(s):  
Extreme Values ◽  
Initial Deflection ◽  
Mathematical Apparatus ◽  
Flat Plates ◽  
Residual Tension ◽  
Different Types ◽  
Definition Of ◽  
Loading Type ◽  
Ansys Workbench

For straightening of low-rigid cylindrical details like shaft and axes different types of loadings are considered which form tension different in size and in distribution. As the perspective direction, it is possible to consider correction by a bend at the influence of the distributed loading with the subsequent hardening of a billet by superficial plastic deformation based on a cross cheesing of it by flat plates. Purpose of the work was to define tension of the billet at cross correction for the choice of more effective type of loading and processing rational modes. The mathematical apparatus was used based on laws of the theory of an elastoplastic solid and Ansys Workbench software package. Novelty is the research of effective methods of loading at cross correction of cylindrical details. As a result of analytical calculations, value of the residual tension providing correction of cylindrical details was determined. Residual tension necessary for correction of cylindrical details depends on an initial deflection, material and preparation rate. Tension of cylindrical details was defined depending on a type of the application of cross loadings. Bend tension for correction of a shaft at distributed loading is less, than tension from action of cross force. For correction of a shaft with a diameter of 10 mm, 200  mm long and an initial deflection of 0.5  mm it is necessary to create bend tension equal to about 370  MPa. An effective method of loading at cross correction of cylindrical details is the bend at influence of the distributed loading. The received extreme values of bend coefficients are from 5.3 to 5.5 for all cases of shaft rigidity at correction by cross bend at distributed loading with l/L relation equal to 0.8. The developed mathematical model gives quite reliable values of the residual tension providing correction of cylindrical details. The analytical dependence for determination of the size of general deflections and definition of an effective loading type can be recommended for practical use in production for achievement of precision accuracy of low-rigid details like shaft.

Analysis of machine elements in shape of helicoidal shell on cylindrical shell

2007 ◽  
Vol 221 (6) ◽  
pp. 627-638 ◽  
Author(s):  
S Savicevic ◽  
S Zekovic
Keyword(s):  
Differential Equation ◽  
Cylindrical Shell ◽  
Cross Section ◽  
Shell Thickness ◽  
Strength Criterion ◽  
Uniform Pressure ◽  
Machine Elements ◽  
The Finite Difference Method ◽  
Automated Determination

A procedure for the automated determination of the geometric parameters of a helicoidal shell on a cylindrical one that is applied to machines for special purposes is presented in this paper. A differential equation for the bending of a helicoidal shell subjected to a uniform pressure and a differential equation for the cylindrical shell loaded by a uniformly distributed moment along the helix are used to define the boundary conditions along the cross-section of these shells. The finite difference method is used to solve the differential equation for the bending of a helicoidal shell in MATLAB software. The values of the shell thickness are determined for different parameters using a strength criterion. Different models of the helicoidal shell are analysed.

Coupled Vibrations of Thin-Walled Beams of Open Cross Section

1958 ◽  
Vol 25 (3) ◽  
pp. 373-378 ◽  
Author(s):  
J. M. Gere ◽  
Y. K. Lin
Keyword(s):  
Free Vibration ◽  
Cross Section ◽  
Approximate Formula ◽  
Exact Method ◽  
End Conditions ◽  
Simple Supports ◽  
Thin Walled ◽  
Exact Calculations ◽  
Open Cross Section

Abstract The determination of coupled frequencies of free vibration for beams of nonsymmetric, open cross section is discussed in this paper. Beams with various end conditions, including simple supports, fixed ends and a cantilever, are considered. Results of both exact and approximate analyses are presented. For practical use, a simple approximate formula for determining frequencies of vibration for beams with any end conditions is given. The accuracy of the approximate formula is shown by comparison with results obtained by the exact method. The exact calculations were carried out on an IBM 605 Card Programmed Calculator.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Profil Penyakit Malaria Di Rumah Sakit Islam Siti Rahmah Padang Tahun 2018

2020 ◽  
Vol 2 (2) ◽  
pp. 08-15
Author(s):  
Rahma Triyana ◽  
Salmi Salmi
Keyword(s):  
Observational Study ◽  
Frequency Distribution ◽  
Cross Section ◽  
Laboratory Tests ◽  
Age Group ◽  
Normal Range ◽  
Cross Sectional ◽  
West Sumatra ◽  
Severity Of The Disease

Malaria is one of the health problems in Indonesia, especially West Sumatra. Determination of the description of Malaria disease in an area is needed to determine the spread and severity of the disease. This study aims to determine the frequency distribution according to age, sex and place of residence, description of the types of Plasmodium causes of Malaria and hematological features in Malaria patients at Siti Rahmah Padang Hospital in 2018. This type of research is a descriptive observational study with an approach or design cross section (cross sectional). The frequency distribution of Malaria sufferers in Siti Rahmah Padang Hospital in 2018 according to the highest age was in the age group 21-30 years as many as 28 cases (36.8%), the highest sex among men was 46 (60.5%) and the highest number of residences was found in Koto Tangah sub-district there were 31 cases (40.8%). The type of Plasmodium found in Malaria cases in Siti Rahmah Padang Hospital in 2018 was P. vivax (73 cases (96.05%)) and P. falciparum (3 cases (3.95%)). The results of laboratory tests on Hb, hematocrit, platelet and leukocyte levels in Malaria positive patients in Siti Rahmah Padang Hospital in 2018 were in the normal range.

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