scholarly journals Nonlinear Dynamics of Heavy Structures

2021 ◽  
Vol 346 ◽  
pp. 03037
Author(s):  
Yury Izvekov ◽  
Oleg Tulupov ◽  
Irina Kinzina ◽  
Alexey Kanel-Belov
Keyword(s):  
Nonlinear Dynamics ◽  
Calculated Data ◽  
Small Dimension ◽  
Overhead Crane ◽  
Frame Field ◽  
Load Carrying ◽  
Wild Cards ◽  
Structural Risk ◽  
The Moment ◽  
Heavy Structure

At the moment, not enough attention is paid to different aspects of nonlinear dynamics for heavy structures. In this article we attempt to create a mathematical model for finding a frame (field) with predictable dynamic pattern of load-carrying capability for a heavy structure based оn the parameters of its reliable (failure-free, low-risk) operation. It is difficult to find a solution for this problem now but the following algorithm can be applied. Small dimension projection is first obtained for orthonormal vectors determining the structural load-carrying capability. Then we use available methods to find a field where any relationship (functional, logical) can be obtained between the rules (wild cards) and the load-carrying capability displayed by a heavy structure. This article carries on the cycle of activities on structural risk analysis involving heavy structures. Numerical and calculated data are based on previous studies. The analysis is performed on a metallurgical overhead crane. The obtained findings are used for adopting various engineering solutions at different stages of heavy structure operation.

scholarly journals Probabilistic modeling of crack growth in large structures

2020 ◽  
Vol 329 ◽  
pp. 03021
Author(s):  
Yury Izvekov ◽  
Olga Torshina ◽  
Alexander Anisimov ◽  
Galina Kameneva ◽  
Tatyana Bondarenko
Keyword(s):  
Distribution Function ◽  
Risk Analysis ◽  
Crack Growth ◽  
Calculated Data ◽  
Critical Issue ◽  
Distribution Functions ◽  
Overhead Crane ◽  
Cyclic Resistance ◽  
Large Structures ◽  
Structural Risk

The allowance for various defects including cracks represents a critical issue related to structural risk analysis. The complexity and the ambiguity involved with such allowance for the amount and growth of defects (cracks) is demonstrated on the real structure of a metallurgical overhead crane. The problem of distribution function conversion must be solved to allow for any variations in defects starting from the point of time when the initial (technological) defectiveness is determined and ending with the estimated time of risk analysis. Due to the lack of data on cyclic resistance to cracking for Вст3сп5 steel, it does not yet seem possible to construct the distribution functions and to determine the estimated theoretical average and dispersion of crack sizes. However, by using the previously obtained calculated data on active stresses and strains, it is now possible to simulate growth of cracks based on Weibull distribution. Different engineering solutions can be accepted at various stages of operating large structures, according to the obtained results.

Bending Behavior of Simply-Supported Sandwich Beams Subjected to Large Deflection

2018 ◽  
Vol 777 ◽  
pp. 569-574
Author(s):  
Zhong You Xie
Keyword(s):  
Energy Absorption ◽  
Large Deflection ◽  
Absorption Efficiency ◽  
Sandwich Beams ◽  
Element Simulation ◽  
Energy Absorption Efficiency ◽  
Load Carrying ◽  
Absorption Performance ◽  
Bending Behavior ◽  
The Moment

Due to thin skins and soft core, it is apt to local indentation inducing the concurrence of geometrical and material nonlinearity in sandwich structures. In the paper, finite element simulation is used to investigate the bending behavior of lightweight sandwich beams under large deflection. A modified formulation for the moment at mid-span section of sandwich beams under large deflection is presented, and energy absorption performance is assessed based on energy absorption efficiency. In addition, it is found that no local indentation arises initially, while later that increases gradually with loading displacement increasing. The height of the mid-span section as well as load-carrying capacity decreases significantly with local indentation depth increasing.

scholarly journals Effect of moisture content on the load carrying capacity and stiffness of corner wood-based and plastic joints

BioResources ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 8640-8655
Author(s):  
Eliška Máchová ◽  
Nadežda Langová ◽  
Roman Réh ◽  
Pavol Joščák ◽  
Ľuboš Krišťák ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Moisture Content ◽  
Carrying Capacity ◽  
Calculated Data ◽  
Statistical Processing ◽  
Epoxy Adhesive ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Effect Of Moisture

The effect of moisture content on mechanical properties of corner furniture joints was evaluated for when different joining methods and materials were used. Results included statistical processing of the measured and calculated data and evaluation of the effect of selected factors on mechanical properties of joints caused by using mechanical fasteners and glue. The load-carrying capacity and stiffness of corner joints were investigated in two environments, humid and dry, with standard conditions for temperature and pressure, i.e., dry environment had a temperature of 23 °C ± 2 °C and relative humidity of 45% ± 5%, and the humid environment had a temperature of 23 °C ± 2 °C and relative humidity of 90% ± 5%. The two types of materials used were particleboard (PB) with a thickness of 12 mm and artificial stone (plastic) with a thickness of 12 mm. Both materials were tested individually as well as their combination. Epoxy and polyurethane (PUR) adhesives were used for the glued dowel joints. When the same materials were bonded, maximum load carrying capacity was achieved with PUR adhesive, material combination of plastic-plastic, and moisture content of 90%. The epoxy adhesive was most suitable for bonding materials with different properties.

The Elastic-Softening Failure of Floating Beams

1988 ◽  
Vol 32 (01) ◽  
pp. 37-43
Author(s):  
Paul C. Xirouchakis
Keyword(s):  
Carrying Capacity ◽  
Maximum Load ◽  
Point Load ◽  
Negative Stiffness ◽  
Load Carrying Capacity ◽  
Perfectly Plastic ◽  
Load Carrying ◽  
Elastic Perfectly Plastic ◽  
The Moment ◽  
Elastic Softening

The solution is presented for an infinite elastic-softening floating beam under a point load. The response depends on two nondimensional parameters: the negative stiffness coefficient that characterizes the descending part of the moment-curvature curve, and the nondimensional softening region half-length. The solution exhibits two important features that the elastic-perfectly plastic solution does not show. First, in certain ranges of parameters, the elastic-softening beam has a clearly defined maximum load carrying capacity. Second, in some other ranges of parameters, the elastic-softening beam has a minimum load or residual strength. The beam stiffens up upon further deformation due to the reactions of the water foundation. Critical softening parameters are calculated that separate stable from unstable behavior.

Mechanical properties of confirmat screws corner joints made of native wood and wood-based composites

2019 ◽  
Vol 105 ◽  
pp. 76-84
Author(s):  
NADEŽDA LANGOVÁ ◽  
PAVOL JOŠČÁK
Keyword(s):  
Mechanical Properties ◽  
Carrying Capacity ◽  
Limit State ◽  
Calculated Data ◽  
Statistical Processing ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Characteristic Values ◽  
State Method

Mechanical Properties of Confirmat Screws Corner Joints Made of Native Wood and Wood-Based Composites. The aim of this investigation was to design and determine the mechanical properties of confirmat screws corner joints made of native wood and wood-based composites. The objective of the study was to ascertain the stiffness and load carrying capacity of joints that differed in the diameter and length of confirmat type screw, as well as in the kind of materials. The results include statistical processing of measured and calculated data, and evaluation of the influence of selected factors on mechanical properties. The results are applied to the calculation of the characteristic values of the properties and to the determination of the equations for their calculation for other values of the selected factors. The characteristic values are used for the evaluation of the joints according to the limit state method.

scholarly journals Modification Method of Tooth Profile of Locomotive Traction Gear Based on Rodent Arm Variation

2019 ◽  
Vol 48 (1) ◽  
pp. 89-97
Author(s):  
Lei Lei ◽  
Haichun Ding ◽  
Liang Xuan ◽  
Meichao Qin ◽  
Siyuan Tian ◽  
...  
Keyword(s):  
Power Transmission ◽  
Tooth Profile ◽  
Moment Arm ◽  
Contact Ratio ◽  
Profile Modification ◽  
Tooth Profile Modification ◽  
Element Simulation ◽  
Load Carrying ◽  
The Moment ◽  
Universal Rule

Locomotive traction gear is the key component to power transmission and speed control in locomotive transmission system, which plays an important role in locomotive running speed and load-carrying torque. Considering that there is not universal rule for the method of modification of locomotive gear at present, in this paper, the tooth profile modification is considered with the combination of the increased contact ratio and the variation of the moment arm of action. Based on the principle of modification, according to the load direction after modification, the change rule of moment arm of action after modification is determined, and the interval range of tooth profile modification is also determined. Taking a certain locomotive traction gear as an example, the results obtained through the method of modification which based on combining moment arm of action variation with the increase of contact ratio and the method based on the traditional empirical formula are compared through finite element simulation respectively, on this account to verify the superiority of the theory of modification, which has important theoretical significance for profile modification of locomotive traction gear.

scholarly journals Further Research on an Anti-Swing Control System for Overhead Cranes

2018 ◽  
Vol 8 (1) ◽  
pp. 2598-2603
Author(s):  
B. Spruogis ◽  
A. Jakstas ◽  
V. Gican ◽  
V. Turla ◽  
V. Moksin
Keyword(s):  
Control System ◽  
Maximum Principle ◽  
Phase Trajectory ◽  
Traction Force ◽  
Overhead Crane ◽  
Deviation Angle ◽  
Optimum Trajectory ◽  
Overhead Cranes ◽  
System Changes ◽  
The Moment

A method of reducing load oscillations that occur when overhead crane reaches destination position is presented in the article. The use of control drive scheme of crane bridge and trolley that ensures a smooth phase trajectory transition of the load to the optimum trajectory in accordance with Pontryagin's maximum principle is proposed. Mentioned control system changes the magnitude or direction of the traction force at the moment when the load is located above the destination. It is found that the degree of change of the traction force depends on the hoisting rope deviation angle from vertical. This study was conducted in order to provide more accurate and fast handling of loads by overhead crane.

scholarly journals MODELLING DEFORMATION BEHAVIOUR OF RC BEAMS ATTRIBUTING TENSION-STIFFENING TO TENSILE REINFORCEMENT

2009 ◽  
Vol 1 (3) ◽  
pp. 141-147 ◽  
Author(s):  
Donatas Salys ◽  
Gintaris Kaklauskas ◽  
Viktor Gribniak
Keyword(s):  
Deformation Behaviour ◽  
Tensile Force ◽  
Material Model ◽  
Rc Beams ◽  
Tension Stiffening ◽  
Load Carrying ◽  
Reinforced Steel ◽  
Internal Forces ◽  
The Moment ◽  
Stiffening Effect

After cracking, the stiffness of the member along its length varies, which makes the calculation of deformations complicated. In a cracked member, stiffness is largest in the section within the uncracked region while remains smallest in the cracked section. This is because in the cracked section, tensile concrete does not contribute to the load carrying mechanism. However, at intermediate sections between adjacent cracks, concrete around reinforcement retains some tensile force due to the bond-action that effectively stiffens member response and reduces deflections. This effect is known as tension-stiffening. This paper discusses the tension-stiffening effect in reinforced concrete (RC) beams. Numerical modelling uses the approach based on tension-stiffening attributed to tensile reinforcement. A material model of reinforced steel has been developed by inverse analysis using the moment-curvature diagrams of RC beams. Total stresses in tensile reinforcement consist of actual stresses corresponding to the average strain of the steel and additional stresses due to tension-stiffening. The carried out analysis employed experimental data on RC beams tested by the authors. The beams had a constant cross section but a different amount of tensile reinforcement. It has been shown that additional (tension-stiffening) stresses in the steel depend on the area of reinforcement. However, the resulting internal forces are less dependent on the amount of reinforcement.

Tearing analysis of PVC coated fabric under uniaxial and biaxial central tearing tests

2020 ◽  
pp. 152808372093451
Author(s):  
Han Bao ◽  
Minger Wu ◽  
Xubo Zhang
Keyword(s):  
Crack Propagation ◽  
Failure Modes ◽  
Load Ratio ◽  
Theoretical Models ◽  
Crack Orientation ◽  
Load Distributions ◽  
Load Carrying ◽  
Crack Tips ◽  
The Moment ◽  
Two Parameters

In this study, detailed uniaxial and biaxial central tearing tests of a type of PVC coated polyester fiber fabric for buildings were carried out. The characteristics of the damage morphology, the formation of the triangle area at the crack tip, crack propagation, and failure modes during the entire tearing process were studied. The influence of crack orientation, crack length, and load ratio on tearing behaviors were analyzed, and it was found that the two parameters of crack orientation and length could be combined into a single variable of the number of cutting-off yarns in the direction perpendicular to crack propagation. For the uniaxial central tearing test, four widely used theoretical models were used to fit the experimental results, which led to the conclusion that Thiele’s empirical formula was the most suitable theory for predicting the tearing strength of PVC fabrics. Finally, the strain of all yarns across the crack section before and at the moment of crack propagation was recorded by the DIC equipment, and the load borne by each yarn was calculated based on the uniaxial tension curve of this material. In this way, the strain and load distributions were obtained for the first time, from which it was observed that the maximum strain almost always concentrated in the del-zone at crack tips, and the number of cutting-off yarns significantly affected the strain distribution. Specifically, the more yarns were cut off, the more difficult it was for other yarns far from the crack to exert their load-carrying capacity.

scholarly journals The Moment Map: Nonlinear Dynamics of Density Evolution via a Few Moments

2006 ◽  
Vol 5 (3) ◽  
pp. 403-434 ◽  
Author(s):  
D. Barkley ◽  
I. G. Kevrekidis ◽  
A. M. Stuart
Keyword(s):  
Nonlinear Dynamics ◽  
Moment Map ◽  
Density Evolution ◽  
The Moment
Sign in / Sign up

Export Citation Format

Share Document