Buckling of Short, Thin-Walled Cylinders Under Combined Loading

1991 ◽  
Vol 113 (4) ◽  
pp. 306-311 ◽  
Author(s):  
P. Goltermann
Keyword(s):  
Yield Stress ◽  
Carrying Capacity ◽  
Critical Stress ◽  
Plate Theory ◽  
Yield Condition ◽  
Offshore Structures ◽  
Combined Loading ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Actual Geometry

Short cylindrical shells are often used in offshore structures. Such cylinders are loaded by axial compression as well as hydrostatical pressure. The load-carrying capacity is for practical purposes determined for each of the two load cases separately. The determination of the load-carrying capacity for a combined loading is then based on a combination of those two load-carrying capacities. This combination differs from code to code and has a significant influence on the load-carrying capacity. This paper presents a rational way of estimating the capacity by using simple, well-known theories. The elastic, critical stress (fe) of a perfect cylinder is estimated according to the classic shell theory for the two load cases, and the respective knock-down factors (α) are calculated according to a code or according to Koiter’s classic stability theory. This leads to an estimate of the ratio between actual stress and the elastic, critical stress (fe·α) of the imperfect cylinder in the two load cases. The membrane stresses and the bending stresses due to the oval imperfection of the cylinder are calculated according to the plate theory, in which the stiffness is reduced corresponding to those ratios. The capacity is defined as the load level at which a point yields according to von Mises’ yield condition. The method is easily applicable for practical purposes and has the advantage that it estimates the capacity at the actual geometry, yield stress, imperfection level and load combination, and thus enables a better estimation. The paper shows that the interaction curves depend severely on the geometry, the level of imperfection, and the size of the yield stress.

Crushing of a Tube Between Rigid Plates

1963 ◽  
Vol 30 (3) ◽  
pp. 391-395 ◽  
Author(s):  
John A. DeRuntz ◽  
P. G. Hodge
Keyword(s):  
Carrying Capacity ◽  
Yield Condition ◽  
Deformation Curve ◽  
Load Carrying Capacity ◽  
Initial Yield ◽  
Thin Tube ◽  
Load Carrying

The load-deformation curve is obtained for a thin tube crushed between two parallel, rigid plates. It is found that the influence of geometry changes after initial yield results in increased load-carrying capacity. In addition, the effects on the yield condition due to direct stress and shear are quantitatively discussed.

scholarly journals Investigation of ANN Architecture for Predicting Load-Carrying Capacity of Castellated Steel Beams

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Thuy-Anh Nguyen ◽  
Hai-Bang Ly ◽  
Van Quan Tran
Keyword(s):  
Yield Stress ◽  
Carrying Capacity ◽  
Design Guidelines ◽  
Steel Beams ◽  
Load Carrying Capacity ◽  
Ann Model ◽  
Efficient Design ◽  
Vertical Projection ◽  
Geometrical Properties ◽  
Load Carrying

Castellated steel beams (CSB) are an attractive option for the steel construction industry thanks to outstanding advantages, such as the ability to exceed large span, lightweight, and allowing flexible arrangement of the technical pipes through beams. In addition, the complex localized and global failures characterizing these structural members have led researchers to focus on the development of efficient design guidelines. This paper aims to propose an artificial neural network (ANN) model with optimal architecture to predict the load-carrying capacity of CSB with a scheme of the simple beam bearing load located at the center of the beam. The ANN model is built with 9 input variables, which are essential parameters equivalent to the geometrical properties and mechanical properties of the material, such as the overall depth of the castellated beam, the vertical projection of the inclined side of the opening, the web thickness, the flange width, the flange thickness, the width of web post at middepth, the horizontal projection of inclined side of the opening, the minimum web yield stress, and the minimum flange yield stress. The output variable is the load-carrying capacity of the CSB. With the optimal ANN architecture [9-1-1] containing one hidden layer, the performance of the ANN model is evaluated based on statistical criteria such as R2, RMSE, and MAE. The results show that the optimal ANN model is a highly effective predictor of the load-carrying capacity of the CSB with the best value of R2 = 0.989, RMSE = 3.328, and MAE = 2.620 for the testing part. The ANN model seems to be the best algorithm of machine learning for predicting the CSB load-carrying capacity.

An Assessment on the Plastic Capacity of Pipe-in-Pipe Systems Under Damage Progression Effect

2021 ◽  
Vol 88 (4) ◽  
Author(s):  
Farhad Davaripour ◽  
Bruce W.T. Quinton ◽  
Kenton Pike
Keyword(s):  
Carrying Capacity ◽  
Phase 1 ◽  
Lateral Load ◽  
External Pressure ◽  
Combined Loading ◽  
Load Carrying Capacity ◽  
Plastic Damage ◽  
Damage Progression ◽  
Structural Resistance ◽  
Load Carrying

Abstract In recent years, pipe-in-pipe (PiP) systems have been employed in an increasing number of subsea projects. According to the previous studies, the external pressure required to develop the initial local buckle on the PiP system is significantly higher than the pressure required to propagate the buckle along the system. In this respect, it is reasonable to investigate a novel topic where the propagation of buckle is induced by a lateral interference load instead of external pressure (e.g., diagonal fishing gear impact). On this subject, the recent studies showed the progression of plastic damage along a single-walled pipe, which is induced by a lateral load, could significantly lower the load-carrying capacity of the pipe. The present study investigates this finding for a PiP solution under a two-phase loading condition: in phase 1, the PiP solution is subject to 75 mm perpendicular indentation, and in phase 2, the resulting plastic damage in phase 1 is translated and induced longitudinally along with the PiP system. Furthermore, using finite element analyses, the effect of combined loading (axial and lateral load) on the load-carrying capacity of the PiP specimen is investigated. The test results show that upon the initiation of damage progression, the load-carrying capacity of the PiP specimen (against the lateral indentation) declines by 10%. Also, the numerical results show that the structural resistance of a PiP specimen against a lateral indentation drops significantly when the inner pipe is subject to axial compression.

scholarly journals Fuzzy Probabilistic Analysis of Steel Structure Focused on Reliability Design Concept of Eurocodes

2007 ◽  
Vol 12 (3) ◽  
pp. 371-382 ◽  
Author(s):  
Z. Kala
Keyword(s):  
Yield Stress ◽  
Carrying Capacity ◽  
Steel Structure ◽  
Statistical Characteristics ◽  
Load Carrying Capacity ◽  
Reliability Design ◽  
Steel Members ◽  
Load Carrying ◽  
Load Action ◽  
European Standards

The modern unification of the European standards EUROCODE requires securing a constant quality of metallurgical production in the EU countries. In this paper, experimentally found statistical characteristics of yield stress, ultimate tensile strength and ductility of Czech and Austrian steel are presented. In the probabilistic reliability analysis, the experimentally found yield stress histograms of structural steel S235 of both Czech and Austrian manufacturing processes are considered as basic parameters. The reliability of steel members designed according to EUROCODE 3 is investigated. The objective of the studies is the verification of partial safety factors of load-carrying capacity, and of load action given in the standard EN1990. Differences in failure probabilities of steel members of Czech and Austrian production are studied in connection with the influence of model fuzzy uncertainties in the determination of load action and load-carrying capacity values.

Failure Analysis of Fiber Reinforced Composite Materials Used in Malaysian Industries

2007 ◽  
Vol 4 (2) ◽  
pp. 41
Author(s):  
Jamaluddin Mahmud ◽  
Wahyu Kuntjoro ◽  
Aidah Jumahat
Keyword(s):  
Composite Materials ◽  
Carrying Capacity ◽  
Plate Theory ◽  
Load Carrying Capacity ◽  
Reinforced Composite ◽  
Load Carrying ◽  
Actual Load ◽  
Fortran 90 ◽  
Materials Used ◽  
Discrete Layer

The main objective of this paper is to determine the curves bounding the actual load carrying capacity in terms of the First Ply Failure and the Last Ply Failure of composite materials used in Malaysian Industries. A mathematical model and computational model are presented for the analysis. Higher Order Shear Deformation plate theory is employed to predict the deformation of the plate. The selected material properties through thickness is used and accommodated by a discrete layer approach. A program based on finite element method is developed using Fortran-90 to determine the lamina stresses. These stresses are then used in the present failure model to determine the First Ply Failure and Last Ply Failure, by progressively reducing the stiffness of the laminas. Finally, the First Ply Failure and Last Ply failure results are analysed, in terms of lower and upper bound within which the true load carrying capacity lies.

scholarly journals Failure Analysis of Fiber Reinforced Composite Materials Used in Malaysian Industries

2007 ◽  
Vol 4 (2) ◽  
pp. 41
Author(s):  
Jamaluddin Mahmud ◽  
Wahyu Kuntjoro ◽  
Aidah Jumahat
Keyword(s):  
Composite Materials ◽  
Carrying Capacity ◽  
Plate Theory ◽  
Load Carrying Capacity ◽  
Reinforced Composite ◽  
Load Carrying ◽  
Actual Load ◽  
Fortran 90 ◽  
Materials Used ◽  
Discrete Layer

The main objective of this paper is to determine the curves bounding the actual load carrying capacity in terms of the First Ply Failure and the Last Ply Failure of composite materials used in Malaysian Industries. A mathematical model and computational model are presented for the analysis. Higher Order Shear Deformation plate theory is employed to predict the deformation of the plate. The selected material properties through thickness is used and accommodated by a discrete layer approach. A program based on finite element method is developed using Fortran-90 to determine the lamina stresses. These stresses are then used in the present failure model to determine the First Ply Failure and Last Ply Failure, by progressively reducing the stiffness of the laminas. Finally, the First Ply Failure and Last Ply failure results are analysed, in terms of lower and upper bound within which the true load carrying capacity lies.

scholarly journals Analysis of Gear Wheel-shaft Joint Characterized by Comparable Pitch Diameter and Mounting Diameter

10.14311/472 ◽  
2003 ◽  
Vol 43 (5) ◽  
Author(s):  
J. Ryś ◽  
H. Sanecki ◽  
A. Trojnacki
Keyword(s):  
Carrying Capacity ◽  
Small Difference ◽  
Design Procedure ◽  
Gear Wheel ◽  
Combined Loading ◽  
Strength Analysis ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Load Intensity ◽  
New Generation

This paper presents the design procedure for a gear wheel-shaft direct frictional joint. The small difference between the operating pitch diameter of the gear and the mounting diameter of the frictional joint is the key feature of the connection. The contact surface of the frictional joint must be placed outside the bottom land of the gear, and the geometry of the joint is limited to the specific type of solutions.The strength analysis is based on the relation between the torque and statistical load intensity of the gear transmission. Several dimensionless parameters are introduced to simplify the calculations. Stress-strain verifying analysis with respect to combined loading, the condition of appropriate load-carrying capacity of the frictional joint and the fatigue strength of the shaft are applied to obtain the relations between the dimensions of the joint and other parameters. The final engineering solution may then be suggested. The approach is illustrated by a numerical example.The proposed procedure can be useful in design projects for small, high-powered modern reducers and new-generation geared motors, in particular when manufactured in various series of types.

Influence of Yield Strength Variability over Cross-Section to Steel Beam Load-Carrying Capacity

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala
Keyword(s):  
Yield Strength ◽  
Cross Section ◽  
Carrying Capacity ◽  
Bending Moment ◽  
Statistical Characteristics ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Strength Variability ◽  
Hot Rolled ◽  
Hot Rolled Steel

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.

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