Work principle in inelastic buckling analysis of axially compressed rectangular plates

2017 ◽  
Vol 14 (2) ◽  
pp. 95-100
Author(s):  
U.G. Eziefula ◽  
D.O. Onwuka ◽  
O.M. Ibearugbulem
Keyword(s):  
Rectangular Plate ◽  
Variational Principles ◽  
Error Function ◽  
Mathematical Formulation ◽  
Plasticity Theory ◽  
Maclaurin Series ◽  
Inelastic Buckling ◽  
Content Type ◽  
Aspect Ratios ◽  
Buckling Coefficient

Purpose The purpose of this paper is to analyze the inelastic buckling of a rectangular thin flat isotropic plate subjected to uniform uniaxial in-plane compression using a work principle, a deformation plasticity theory and Taylor–Maclaurin series formulation. Design/methodology/approach The non-loaded longitudinal edges of the rectangular plate are clamped, whereas the loaded edges are simply supported (CSCS). Total work error function is applied to Stowell’s plasticity theory in the derivation of the inelastic buckling equation. Mathematical formulation of the Taylor–Maclaurin series deflection function satisfied the boundary conditions of the CSCS rectangular plate. The critical inelastic load of the plate is then derived by applying variational principles. Findings Values of the plate buckling coefficient are calculated using various values of moduli ratio for aspect ratios ranging from 0.1 to 1.0, in intervals of 0.1. The accuracy of the proposed technique is validated by comparing the results obtained in the present study with solutions from a previous investigation. The percentage differences in the values of the buckling coefficient ranged from −0.122 to −4.685 per cent. Originality/value The results indicate that the work principle approach can be used as an alternative approximate method for analyzing inelastic buckling of rectangular thin flat isotropic plates under uniform in-plane compressive loads.

scholarly journals Analysis of inelastic buckling of rectangular plates with a free edge using polynomial deflection functions

2020 ◽  
Vol 11 (1) ◽  
pp. 15-21
Author(s):  
Uchechi G. Eziefula
Keyword(s):  
Boundary Conditions ◽  
Rectangular Plate ◽  
Polynomial Function ◽  
Free Edge ◽  
Rectangular Plates ◽  
Maclaurin Series ◽  
Inelastic Buckling ◽  
Aspect Ratios ◽  
Isotropic Plates ◽  
Deformation Plasticity

AbstractThe inelastic buckling behaviour of different rectangular thin isotropic plates having a free edge is studied. Various combinations of boundary conditions are subject to in-plane uniaxial compression and each rectangular plate is bounded by an unloaded free edge. The characteristic deflection function of each plate is formulated using a polynomial function in form of Taylor–Maclaurin series. A deformation plasticity approach is adopted and the buckling load equation is modified using a work principle technique. Buckling coefficients of the plates are calculated for various aspect ratios and moduli ratios. Findings obtained from the investigation are found to reasonably agree with data published in the literature.

Robustness evaluation of CSMM based finite element for simulation of shear critical hollow RC bridge piers

2019 ◽  
Vol 37 (1) ◽  
pp. 313-344
Author(s):  
Vijay Kumar Polimeru ◽  
Arghadeep Laskar
Keyword(s):  
Finite Element ◽  
Earthquake Engineering ◽  
Bridge Piers ◽  
Fe Model ◽  
Content Type ◽  
Aspect Ratios ◽  
Linear Behavior ◽  
Non Linear ◽  
Reversed Cyclic ◽  
Rc Bridge Piers

Purpose The purpose of this study is to evaluate the effectiveness of two-dimensional (2D) cyclic softened membrane model (CSMM)-based non-linear finite element (NLFE) model in predicting the complete non-linear response of shear critical bridge piers (with walls having aspect ratios greater than 2.5) under combined axial and reversed cyclic uniaxial bending loads. The effectiveness of the 2D CSMM-based NLFE model has been compared with the widely used one-dimensional (1D) fiber-based NLFE models. Design/methodology/approach Three reinforced concrete (RC) hollow rectangular bridge piers tested under reversed cyclic uniaxial bending and sustained axial loads at the National Centre for Research on Earthquake Engineering (NCREE) Taiwan have been simulated using both 1D and 2D models in the present study. The non-linear behavior of the bridge piers has been studied through various parameters such as hysteretic loops, energy dissipation, residual drift, yield load and corresponding drift, peak load and corresponding drift, ultimate loads, ductility, specimen stiffness and critical strains in concrete and steel. The results obtained from CSMM-based NLFE model have been critically compared with the test results and results obtained from the 1D fiber-based NLFE models. Findings It has been observed from the analysis results that both 1D and 2D simulation models performed well in predicting the response of flexure critical bridge pier. However, in the case of shear critical bridge piers, predictions from 2D CSMM-based NLFE simulation model are more accurate. It has, thus, been concluded that CSMM-based NLFE model is more accurate and robust to simulate the complete non-linear behavior of shear critical RC hollow rectangular bridge piers. Originality/value In this study, a novel attempt has been made to provide a rational and robust FE model for analyzing shear critical hollow RC bridge piers (with walls having aspect ratios greater than 2.5).

Minimum carbon dioxide emission based selection of traffic route with unsignalised junctions in tandem network

2019 ◽  
Vol 30 (3) ◽  
pp. 657-675 ◽  
Author(s):  
Anand Jaiswal ◽  
Cherian Samuel ◽  
Chirag Chandan Mishra
Keyword(s):  
Carbon Dioxide ◽  
Queuing Theory ◽  
Mathematical Formulation ◽  
Carbon Dioxide Emission ◽  
Arrival Rate ◽  
Selection Strategy ◽  
Service Rate ◽  
Content Type ◽  
Fuel Consumption Rate ◽  
Route Choices

Purpose The purpose of this paper is to provide a traffic route selection strategy based on minimum carbon dioxide (CO2) emission by vehicles over different route choices. Design/methodology/approach The study used queuing theory for Markovian M/M/1 model over the road junctions to assess total time spent over each of the junctions for a route with junctions in tandem. With parameters of distance, mean service rate at the junction, the number of junctions and fuel consumption rate, which is a function of variable average speed, the CO2 emission is estimated over each of the junction in tandem and collectively over each of the routes. Findings The outcome of the study is a mathematical formulation, using queuing theory to estimate CO2 emissions over different route choices. Research finding estimated total time spent and subsequent CO2 emission for mean arrival rates of vehicles at junctions in tandem. The model is validated with a pilot study, and the result shows the best vehicular route choice with minimum CO2 emissions. Research limitations/implications Proposed study is limited to M/M/1 model at each of the junction, with no defection of vehicles. The study is also limited to a constant mean arrival rate at each of the junction. Practical implications The work can be used to define strategies to route vehicles on different route choices to reduce minimum vehicular CO2 emissions. Originality/value Proposed work gives a solution for minimising carbon emission over routes with unsignalised junctions in the tandem network.

scholarly journals Influence of the patch loading length on the buckling coefficient of longitudinally stiffened plate girders

2019 ◽  
Author(s):  
Nelson Loaiza ◽  
Carlos Graciano ◽  
Rolando Chacón
Keyword(s):  
Elastic Buckling ◽  
Stiffened Plate ◽  
Element Analysis ◽  
Geometrical Properties ◽  
Plate Girders ◽  
Linear Finite Element ◽  
Aspect Ratios ◽  
Buckling Behavior ◽  
Buckling Coefficient ◽  
Patch Loading

This paper aims at investigating the effect of the bearing length on the elastic buckling behavior of longitudinally stiffened girder webs subjected to patch loading. Buckling coefficients are calculated by means of linear finite element analysis. Furthermore, a parametric analysis is performed to study the influence of other geometric parameters such as the panel aspect ratio and the geometrical properties of the longitudinal ones. Buckling coefficients of longitudinally stiffened girder webs are computed numerically. The results show that the buckling coefficient for longitudinally stiffener girder webs increases with the loading length. However, this conclusion is considerably affected by other factors such as the position of the stiffener, and panel aspect ratios.

Inelastic buckling mode interactions and resonance instabilities in thin-walled columns due to the fatigue damage

2020 ◽  
Vol 37 (8) ◽  
pp. 2819-2845 ◽  
Author(s):  
Dragan D. Milašinović ◽  
Petar Marić ◽  
Žarko Živanov ◽  
Miroslav Hajduković
Keyword(s):  
Fatigue Damage ◽  
Great Influence ◽  
Mode Interaction ◽  
Buckling Mode ◽  
Inelastic Buckling ◽  
Content Type ◽  
Effective Stresses ◽  
Stiffness Reduction ◽  
Mode Interactions ◽  
Thin Walled

Purpose The problems of inelastic instability (buckling) and dynamic instability (resonance) have been the subject of extensive investigation and have received wide attention from the structural mechanics community. This paper aims to tackle these problems in thin-walled structures, taking into account geometrical and/or material non-linearity. Design/methodology/approach The inelastic buckling mode interactions and resonance instabilities of prismatic thin-walled columns are analysed by implementing the semi-analytical finite strip method (FSM). A scalar damage parameter is implemented in conjunction with a material modelling named rheological-dynamical analogy to address stiffness reduction induced by the fatigue damage. Findings Inelastic buckling stresses lag behind the elastic buckling stresses across all modes, which is a consequence of the viscoelastic behaviour of materials. Because of the lag, the same column length does not always correspond to the same mode at the elastic and inelastic critical stress. Originality/value This paper presents the influence of mode interactions on the effective stresses and resonance instabilities in thin-walled columns due to the fatigue damage. These mode interactions have a great influence on damage variables because of the fatigue and effective stresses around mode transitions. In its usual semi-analytical form, the FSM cannot be used to solve the mode interaction problem explained in this paper, because this technique ignores the important influence of interaction of the buckling modes when applied only for undamaged state of structure

Surface virtual texturing of the journal bearings of a three-cylinder ethanol engine

2020 ◽  
Vol 72 (9) ◽  
pp. 1059-1073
Author(s):  
Gabriel Welfany Rodrigues ◽  
Marco Lucio Bittencourt
Keyword(s):  
Peer Review ◽  
Power Loss ◽  
Mathematical Formulation ◽  
Surface Texturing ◽  
Elastohydrodynamic Lubrication ◽  
Element Model ◽  
Content Type ◽  
Linear Elastic ◽  
Numerical Experimentation ◽  
Coupling Procedure

Purpose This paper aims to numerically investigate the surface texturing effects on the main bearings of a three-cylinder ethanol engine in terms of the power loss and friction coefficient for dynamic load conditions. Design/methodology/approach The mathematical formulation considers the Partir-Cheng modified Reynolds equation. The mass-conserving Elrod-Adams p-θ model with the JFO approach is used to deal with cavitation. A fluid-structure coupling procedure is considered for the elastohydrodynamic lubrication. Accordingly, a 3-D linear-elastic substructured finite element model obtained from Abaqus is applied Findings Simulations were carried out considering different dimple texture designs in terms of location, depth and radius. The results suggested that there are regions where texturing is more effective. In addition, distinct journal rotation speeds are studied and the surface texture was able to reduce friction and the power loss by 7%. Practical implications The surface texturing can be a useful technique to reduce the power loss on the crankshaft bearing increasing the overall engine efficiency. Originality/value The surface texturing performance in a three-cylinder engine using ethanol as fuel was investigated through numerical experimentation. The results are supported by previous findings. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2019-0380/

Maintenance downtime evaluation in a process bottling plant

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gerald Kenechukwu Inyiama ◽  
Sunday Ayoola Oke
Keyword(s):  
Control Process ◽  
Failure Pattern ◽  
Coefficient Of Determination ◽  
Process Equipment ◽  
Effect Analysis ◽  
Content Type ◽  
Mean Values ◽  
Pareto Analysis ◽  
Aspect Ratios ◽  
Process Plant

PurposeDowntime is a process parameter that substantially impacts on the operating hours and results in production losses, thus motivating maintenance engineers to control process plants. Notwithstanding, the impacting nature of process equipment failure on the operating hours in bottling plants remains inadequately examined. In this paper, the cause-and-effect analysis was used to establish the root cause of the downtime problem and Pareto analysis employed to justify the greatest opportunities for improvement in reducing downtime and increasing reliability levels. Weibull analysis is then conducted on the industrial setting. Novel aspect ratios are proposed.Design/methodology/approachUsing the Weibull failure function of machines as a principal facilitator to produce failure predictions, the downtime behaviour of a process plant was modelled and tested with practical data from a bottling process plant. This research was conducted in a Nigerian process bottling plant where historical data were examined.FindingsThe analysis of the results shows the following principal outcome: First, the machines with the highest and least downtime values are 2 and 5, respectively, with correspondingly mean values of 22.83 and 4.39 h monthly. Second, the total downtime 92.05 and 142.14 h for the observed and target downtime, with a coefficient of determination of 0.5848 was recorded. Third, as month 1 was taken as the base period (target), all the machines, except M5 had accepted performance, indicating proper preventive maintenance plan execution for the bottling process plant. Availability shows a direct relationship between the failure and uptime of the machines and the downtime impacts on production. Two machines had random failure pattern and five machines exhibited a wear-out failure pattern and probably due to old age and wear of components in the machines.Originality/valueThe major contribution of the paper is the Weibull modelling in a unique application to a bottling plant to avoid current practices that use reliability software that is not easily accessible.

The interfacial reliability of through-glass vias for 2.5D integrated circuits

2020 ◽  
Vol 37 (4) ◽  
pp. 181-188
Author(s):  
Omar Ahmed ◽  
Golareh Jalilvand ◽  
Scott Pollard ◽  
Chukwudi Okoro ◽  
Tengfei Jiang
Keyword(s):  
Integrated Circuits ◽  
Material Selection ◽  
Thermal Mismatch ◽  
Element Analysis ◽  
Content Type ◽  
Interfacial Delamination ◽  
Mismatch Strain ◽  
Aspect Ratios ◽  
Interfacial Reliability ◽  
The Impact

Purpose Glass is a promising interposer substrate for 2.5 D integration; yet detailed analysis of the interfacial reliability of through-glass vias (TGVs) has been lacking. The purpose of this paper is to investigate the design and material factors responsible for the interfacial delamination in TGVs and identify methods to improve reliability. Design/methodology/approach The interfacial reliability of TGVs is studied both analytically and numerically. An analytical solution is presented to show the dependence of the energy release rate (ERR) for interfacial delamination on the via design and the thermal mismatch strain. Then, finite element analysis (FEA) is used to investigate the influence of detailed design and material factors, including the pitch distance, via aspect ratio, via geometry and the glass and via materials, on the susceptibility to interfacial delamination. Findings ERR for interfacial delamination is directly proportional to the via diameter and the thermal mismatch strain. Thinner wafers with smaller aspect ratios show larger ERRs. Changing the via geometry from a fully filled via to an annular via leads to lower ERR. FEA results also show that certain material combinations have lower thermal mismatch strains, thus less prone to delamination. Practical implications The results and approach presented in this paper can guide the design and development of more reliable 2.5 D glass interposers. Originality/value This paper represents the first attempt to comprehensively evaluate the impact of design and material selection on the interfacial reliability of TGVs.

Fitness-for-Service Evaluation of Thermal Hot Spots and Corrosion Damage in Cylindrical Pressure Components

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
P. Tantichattanont ◽  
S. M. R. Adluri ◽  
R. Seshadri
Keyword(s):  
Hot Spots ◽  
Structural Integrity ◽  
Variational Principles ◽  
Elastic Shell ◽  
Corrosion Damage ◽  
Pressure Vessels ◽  
Alternative Methods ◽  
Linear Interaction ◽  
Reference Volume ◽  
Aspect Ratios

Thermal hot spots and corrosion damage are typical of damages occurring in pressure vessels and piping. Structural integrity of such components needs to be evaluated periodically to determine “fitness-for-service” (FFS) of the components. In the present paper, three alternative methods for level 2 FFS assessments (as described in API 579) are proposed. They are based on variational principles in plasticity, the m-alpha method, the idea of reference volume, and the concept of decay lengths in shells. Decay lengths in the axial and circumferential directions for cylindrical shells are derived based on elastic shell theories. They are used to specify the reference volume participating in plastic action and the extent of what can be called “local” damage. Interaction between longitudinal and circumferential effects is investigated. A linear interaction curve is shown to give good estimation of the “remaining strength factor” for damage of practical aspect ratios. The stretching and bulging effects due to the damage are also studied. The limit defining the threshold to dominance of stretching action is proposed by using an approximate equilibrium calculation based on yield-line analysis. The effectiveness of the proposed assessments is demonstrated through an example and verified by level 3 inelastic finite element analysis.

Numerical study of nanofluid flow and heat transfer over a rotating disk using Buongiorno’s model

2017 ◽  
Vol 27 (1) ◽  
pp. 221-234 ◽  
Author(s):  
Junaid Ahmad Khan ◽  
M. Mustafa ◽  
T. Hayat ◽  
Mustafa Turkyilmazoglu ◽  
A. Alsaedi
Keyword(s):  
Brownian Motion ◽  
Volume Fraction ◽  
Numerical Study ◽  
Mathematical Formulation ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Rotating Disk ◽  
Content Type ◽  
Buongiorno’S Model ◽  
Buongiorno Model

Purpose The purpose of the present study is to explore a three-dimensional rotating flow of water-based nanofluids caused by an infinite rotating disk. Design/methodology/approach Mathematical formulation is performed using the well-known Buongiorno model which accounts for the combined influence of Brownian motion and thermophoresis. The recently suggested condition of passively controlled wall nanoparticle volume fraction has been adopted. Findings The results reveal that temperature decreases with an increase in thermophoresis parameter, whereas it is negligibly affected with a variation in the Brownian motion parameter. Axial velocity is negative because of the downward flow in the vertical direction. Originality/value Two- and three-dimensional streamlines are also sketched and discussed. The computations are found to be in very good agreement with the those of existing studies in the literature for pure fluid.

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