scholarly journals Calculation of strength of heated curvilinear bar structural elements of tubular cross-sections

2019 ◽  
Vol 5 (2) ◽  
pp. 61-67
Author(s):  
Мykola Voytovych ◽  
◽  
Lev Velychko ◽  
Roman Lampika ◽  
Khrystyna Lishchynska ◽  
...  
Keyword(s):  
Cross Sections ◽  
Structural Elements

Collapse Analysis of Ship Hull Girder Using Hydro-Elastoplastic Beam Model

2018 ◽  
Author(s):  
Han Htoo Htoo Ko ◽  
Akira Tatsumi ◽  
Kazuhiro Iijima ◽  
Masahiko Fujikubo
Keyword(s):  
Cross Sections ◽  
Progressive Collapse ◽  
Ship Hull ◽  
Average Stress ◽  
Beam Model ◽  
Structural Elements ◽  
Hull Girder ◽  
Collapse Analysis ◽  
Strain Relationship ◽  
Collapse Behavior

A method of time-domain collapse analysis of ship hull girder considering the interaction between elastoplastic deformation and hydrostatic/dynamic forces is developed. Ship hull girder is longitudinally divided by conventional beam elements, and progressive collapse behavior of cross sections is simulated by Smith method considering material yielding, buckling and post-buckling of structural elements. Average stress–average strain relationship of structural elements is transformed to average stress–average plastic strain relationship so that it can be treated as pseudo strain-hardening/softening effects. Strip method is used for the calculation of hydrodynamic forces on the hull girder. Hydrodynamic coefficients for cross-sections are calculated by 2D-BEM. In-house analysis code is developed and applied to the collapse analysis of a uniform hull-girder model under impulsive bending loads. The effects of load duration time on the dynamic collapse behavior of the hull girder are discussed.

scholarly journals ToF-SIMS imaging reveals that p-hydroxybenzoate groups specifically decorate the lignin of fibres in the xylem of poplar and willow

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Robyn E. Goacher ◽  
Yaseen Mottiar ◽  
Shawn D. Mansfield
Keyword(s):  
Cross Sections ◽  
Cell Walls ◽  
Tension Wood ◽  
Secondary Ion Mass Spectrometry ◽  
Cell Types ◽  
Structural Elements ◽  
Tof Sims ◽  
Vessel Elements ◽  
The Family ◽  
Secondary Ion

AbstractEsterified phenolics occur as γ-linked lignin acylations in many plant taxa but little is known about the distribution or function of such groups. In the family Salicaceae, p-hydroxybenzoate groups are present in the lignin of poplars (Populus spp.) and willows (Salix spp.). In this study, the distribution of cell wall-bound p-hydroxybenzoate was examined in different tissue and cell types of poplar and willow trees. This analysis showed that p-hydroxybenzoate groups were most prevalent in juvenile stems, and were elevated in tension wood and following nitrogen fertilisation. Closer examination of stem cross-sections using time-of-flight secondary-ion mass spectrometry (ToF-SIMS) directly showed that p-hydroxybenzoate groups occur predominantly in the cell walls of fibres and are largely absent from vessel elements. These results point to a role for ester-linked groups in modifying the syringyl-rich lignin of fibres, perhaps to strengthen the cell walls of these structural elements or to increase lignification rates.

scholarly journals The Usefulness of Pine Timber (Pinus sylvestris L.) for the Production of Structural Elements. Part I: Evaluation of the Quality of the Pine Timber in the Bending Test

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3957 ◽  
Author(s):  
Radosław Mirski ◽  
Dorota Dziurka ◽  
Monika Chuda-Kowalska ◽  
Marek Wieruszewski ◽  
Jakub Kawalerczyk ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Cross Sections ◽  
Modulus Of Elasticity ◽  
Physical And Mechanical Properties ◽  
Bending Test ◽  
Structural Elements ◽  
Forest Division ◽  
Pine Lumber ◽  
Round Cross

The study assessed the quality of pine lumber by marking the modulus of elasticity in the horizontal system. The research material was a plank with the following dimensions: 137 mm wide × 39.50 mm thick × 3485 mm long. The pine wood was obtained by sawing timber in the form of logs with round cross sections and originating from the Forest Division Olesno (50°52′30″ N, 18°25′00″ E). Each long log was sawn to provide four logs of about 3.5 m, which were marked as butt-end logs (O), middle logs (S)—2 items, and top logs (W). The origin of the logs from the trunk (Pinus sylvestris L.) has a significant impact on the physical and mechanical properties of the wood from which they are made. Only butt-end logs (log type O) allows for the production of high-quality timber elements. The pine timber that was evaluated in this paper had a high density of about 570 kg/m3 and a high percentage of timber items were assigned to class C24 and higher (above 50%). The adopted horizontal model of evaluation of the modulus of elasticity gave similar results to those obtained in an evaluation according to the EN-408.

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.

Dynamic Elastic-Plastic Buckling of Structural Elements: A Review

2008 ◽  
Vol 61 (4) ◽  
Author(s):  
D. Karagiozova ◽  
Marcílio Alves
Keyword(s):  
Cross Sections ◽  
High Efficiency ◽  
Transportation Systems ◽  
Review Article ◽  
Experimental Investigations ◽  
Structural Elements ◽  
Postbuckling Behavior ◽  
Elastic Plastic ◽  
Material Characteristics ◽  
Energy Absorbing

Structural elements, which deform inelastically, are often used in energy-absorbing devices due to their simple design and the high efficiency achieved by several buckling deformation mechanisms. The application of light ductile materials in transportation systems and increased loading intensity requires studies on the influence of the rate of loading and material characteristics on dynamic buckling behavior. The present review article is focused on summarizing the state of the art related to the inelastic dynamic stability and postbuckling behavior of various basic structural members. In particular, studies on the dynamic response of axially loaded idealized elastic-plastic models, rods, shells with circular and square cross sections, and long tubes are discussed with consideration given to the influence of the geometric and material characteristics as well as the loading conditions on the buckling phenomena observed in these structural elements. The findings from the theoretical and experimental investigations on the phenomenon of dynamic inelastic buckling reported in this review article are based on 118 references.

scholarly journals Determination of Reinforced Concrete Rectangular Sections Having Plastic Moments Equal to all IPE Profiles

2021 ◽  
Vol 7 (4) ◽  
pp. 614-632
Author(s):  
Sayeh Beroual ◽  
Mohamed Laid Samai
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Cross Sections ◽  
Steel Structures ◽  
Structural Elements ◽  
Great Precision ◽  
Design Charts ◽  
Eurocode 2 ◽  
The Impact

The comparison between steel structures and reinforced concrete structures has always been governed by economy and response to earthquake. Steel structures being lighter and are thus more efficient to resist earthquake. On the other hand, they are more expensive (4 to 5 times). Theoretically, two structural elements having the same plastic moment have an equal failure or collapse load. Different profiles of IPE are realized in industry and all their characteristics are determined with a great precision (weight, geometrical characteristics and thus their plastic moment). Determining equivalent rectangular singly reinforced concrete cross-sections is not easy and seems impossible to be solved analytically. To a given profile it may be found a multitude of equivalent rectangular reinforced concrete cross-section (singly and doubly reinforced with different yield strengths and compositions of concrete). To take into consideration all these factors, it is absolutely necessary to construct three axis design charts with an appropriate choice of system of coordinates in order to cover all possible ranges of different parameters. The choice of all these possible rectangular reinforced concrete sections is governed by the plastic performance of these later. They must be under reinforced, allowing plastification of steel before failure in order to permit the redistribution phenomenon in plastic analysis. The exploitation of these different charts has revealed that the absolute majority of these rectangular reinforced concrete cross-section are reasonably well designed and are in conformity with the dimensions used in practice. The results of the present characterization using Eurocode 2 characteristics are compared to those of CP110. The impact does not seem to be very relevant. Doi: 10.28991/cej-2021-03091677 Full Text: PDF

scholarly journals Stiffness Effects of Structural Elements on the Seismic Response of RC High-Rise Buildings

2018 ◽  
Vol 64 (1) ◽  
pp. 3-20
Author(s):  
D.-P. N. Kontoni ◽  
A. A. Farghaly
Keyword(s):  
Cross Sections ◽  
Rectangular Cross Section ◽  
Time History ◽  
3D Models ◽  
Seismic Load ◽  
Structural Elements ◽  
High Rise ◽  
History Analysis ◽  
Floor Plans ◽  
Overall Performance

Abstract The stiffness of structural elements (columns, beams, and slabs) significantly contributes to the overall stiffness of reinforced concrete (RC) high-rise buildings (H.R.B.s) subjected to earthquake. In order to investigate what percentage each type of element contributes to the overall performance of an H.R.B. under seismic load, the stiffness of each type of element is reduced by 10% to 90%. A time history analysis by SAP2000 was performed on thirteen 3D models of 12-story RC buildings in order to illustrate the contribution of column stiffness and column cross sections (rectangular or square), building floor plans (square or rectangular), beam stiffness and slab stiffness, on building resistance to an earthquake. The stiffness of the columns contributed more than the beams and slabs to the earthquake resistance of H.R.B.s. Rectangular cross-section columns must be properly oriented in order for H.R.B.s and slender buildings to attain the maximum resistance against earthquakes.

scholarly journals Strength Analysis Modelling of Flexible Umbilical Members for Marine Structures

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
S. Sævik ◽  
J. K. Ø. Gjøsteen
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
External Pressure ◽  
Strength Analysis ◽  
Element Formulation ◽  
Structural Elements ◽  
3 Dimensional ◽  
Numerical Studies ◽  
Dimensional Finite Element ◽  
Slender Beams

This paper presents a 3-dimensional finite element formulation for predicting the behaviour of complex umbilical cross-sections exposed to loading from tension, torque, internal and external pressure including bending. Helically wound armours and tubes are treated as thin and slender beams formulated within the framework of small strains but large displacements, applying the principle of virtual displacements to obtain finite element equations. Interaction between structural elements is handled by 2- and 3-noded contact elements based on a penalty parameter formulation. The model takes into account a number of features, such as material nonlinearity, gap and friction between individual bodies, and contact with external structures and with a full 3-dimensional description. Numerical studies are presented to validate the model against another model as well as test data.

Effect of the Shear Force on the Failure of Spatial Concrete Framework Structures

2013 ◽  
Vol 553 ◽  
pp. 67-80 ◽  
Author(s):  
J. Radnić ◽  
A. Harapin ◽  
R. Markić ◽  
N. Grgić ◽  
M. Sunara ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Numerical Model ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Reinforced Concrete Beam ◽  
Normal Strain ◽  
Structural Elements ◽  
Concrete Frame ◽  
Beam Elements ◽  
Shear Bearing Capacity

Firstly, the previously developed numerical model for static analysis of spatial concrete frame structures is briefly described. In this model, cross-sections of structural elements can be of arbitrary shape and formed by various materials, with arbitrary normal stress normal strain relations. This model only includes the effect of normal stresses on the structure failure. Here, it was improved by including the effect of shear forces on the failure of reinforced concrete beam elements. Shear bearing capacity of reinforced concrete section includes the concrete capacity, as well as the shear bearing capacity of longitudinal, transversal and inclined reinforcement bars. The developed numerical model and appropriate software were verified on experimental shear test of a concrete beams. Good agreement was obtained between the experimental and the numerical results. However, further verifications of the presented numerical model are needed.

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