scholarly journals Modernization of the construction of the crane traveling wheel

2021 ◽  
pp. 107
Author(s):  
Nаtalya Fidrovska ◽  
Evgen Slepuzhnikov ◽  
Alexsandr Chernyshenko ◽  
Igor Perevoznyk
Keyword(s):  
Stress State ◽  
Layer Structure ◽  
Experimental Studies ◽  
Vertical Direction ◽  
Lightweight Aggregate ◽  
Middle Layer ◽  
Vibration Acceleration ◽  
Idle Speed ◽  
Drive Wheel ◽  
Steel Material

The article discusses the modernization of the running wheel due to the introduction of an elastic element. The structure, which consists of three layers, the outer ones of which consist of strong steel material, and the middle layer consists of low-strength lightweight aggregate, which can significantly reduce dynamic forces, vibrations and shocks, which increases the reliability of cargo transportation. Calculations have shown that the stress state of a wheel with an elastic insert is less than that of an old-design travel wheel. The decrease in force and elastic factors in the travel wheel, which has an elastic insert, is explained by the fact that the use of an elastic ring leads to an increase in the bending stiffness of the outer ring of the shell. The obtained solution to the problem of the strength of a three-layer structure makes it possible to determine the stresses in the shell depending not only on its geometric parameters, but also on the shear modulus of the filler, which improves the reliability of the design and operation of such structures. Theoretical studies of the stress state of a three-layer cylindrical structure, taking into account the shear energy of the filler, makes it possible to assess the strength of such a structure and give certain recommendations for its use. Experimental studies that were carried out on an operating overhead crane fully confirmed a very significant reduction in oscillatory processes in travel wheels. The level of vibration acceleration in the vertical direction on the modernized drive wheel is almost 3 times less than the level of vibration acceleration on the drive wheel at idle speed of a conventional design.

scholarly journals Experimental Study on Mechanical and Sensing Properties of Smart Composite Prestressed Tendon

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2087 ◽  
Author(s):  
Danhui Dan ◽  
Pengfei Jia ◽  
Guoqiang Li ◽  
Po Niu
Keyword(s):  
Stress State ◽  
Carbon Fibers ◽  
Prestressed Concrete ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Tension Force ◽  
Smart Composite ◽  
Steel Wires ◽  
Sensing Performance

It is typically difficult for engineers to detect the tension force of prestressed tendons in concrete structures. In this study, a smart bar is fabricated by embedding a Fiber Bragg Grating (FBG) in conjunction with its communication fiber into a composite bar surrounded by carbon fibers. Subsequently, a smart composite cable is twisted by using six outer steel wires and the smart bar. Given the embedded FBG, the proposed composite cable simultaneously provides two functions, namely withstanding tension force and self-sensing the stress state. It can be potentially used as an alternative to a prestressing reinforcement tendon for prestressed concrete (PC), and thereby provide a solution to detecting the stress state of the prestressing reinforcement tendons during construction and operation. In the study, both the mechanical properties and sensing performance of the proposed composite cable are investigated by experimental studies under different force standing conditions. These conditions are similar to those of ordinary prestressed tendons of a real PC components in service or in a construction stage. The results indicate that the proposed smart composite cable under the action of ultra-high pretension stress exhibits reliable mechanical performance and sensing performance, and can be used as a prestressed tendon in prestressed concrete structures.

scholarly journals Edge screw withdrawal resistance in conventional particleboard and OSB: Influence of the particles type

2007 ◽  
pp. 109-117
Author(s):  
Jovan Miljkovic ◽  
Mladjan Popovic ◽  
Milanka Djiporovic-Momcilovic ◽  
Ivana Gavrilovic-Grmusa
Keyword(s):  
Oriented Strand Board ◽  
Layer Structure ◽  
Middle Layer ◽  
Root Diameter ◽  
Mean Values ◽  
Pilot Hole ◽  
Wood Particles ◽  
Screw Withdrawal ◽  
Insight Into

This research was based on presumption that the changes in size and shape of wood particles are expected to have certain impact on the particleboard quality in general. Since the conventional particleboard (PB) and oriented strand board (OSB) were built of the quite diverse wood particles, they present interesting specimens in the comparison tests. In this work, the influence of the wood particles type on the edge screw holding performance of conventional particleboard and OSB was investigated. Those tests were obtained with the screw diameters of 4.0 mm, 4.5 mm and 5 mm. Depth of embedment was 30 mm for all tests and with the pilot-hole diameter kept in the range of 80-90% in respect of the screw root diameter. Additional tests of the thickness density profile and tensile strength perpendicular to the surface of the board were conducted. Since the middle layer structure of the particleboard embeds the screw body, both mentioned parameters are considered important in the aspect of the quality of the edge screw holding performance. In order to have further insight into the conformation of the middle layer the image survey was obtained on the split board section presenting the surface of the middle layer. Significant differences in the SWR performance of OSB and PB was recorded at all screw diameters. For the screw withdrawal tests parameters OSB samples showed 56-73% superior mean values then conventional PB. On the other hand, the OSB showed wider dispersions of measured withdrawal forces at all screw diameters, which might present some of the problems in certain engineering and project calculations.

Nonlinear Dynamics of Orthogonal Metal Cutting: Experimental Studies

1999 ◽  
Author(s):  
Chee-Hoe Foong ◽  
Marian Wiercigroch ◽  
William F. Deans
Keyword(s):  
Nonlinear Dynamics ◽  
Cast Iron ◽  
Metal Cutting ◽  
Thrust Force ◽  
Experimental Studies ◽  
Vertical Direction ◽  
Systematic Analysis ◽  
Orthogonal Metal Cutting ◽  
Time Histories ◽  
Force Components

Abstract The elimination of chatter is one of the major aims in machining to improve geometrical accuracy and surface finish. In this study, occurrence of chatter was investigated experimentally using a specially designed rig by examining time histories of the cutting and thrust force components. A broad experimental study was conducted using brass, cast iron and aluminium samples. It was found that by changing the horizontal stiffness of the rig, the thrust force variations (in the vertical direction) were completely eliminated for the cast iron samples. A systematic analysis of the chip formation for the aluminium alloy is presented.

Experimental studies of the effect of concentrated dynamic loads on a three-layer structure with a filler

2021 ◽  
pp. 20-21
Author(s):  
Keyword(s):  
Comparative Analysis ◽  
Glass Fiber ◽  
Impact Loading ◽  
Layer Structure ◽  
Experimental Studies ◽  
Theoretical Data ◽  
Dynamic Loads ◽  
Bearing Layer

The results of experimental studies of the effect of concentrated dynamic loads on a three-layer structure with glass fiber filler are presented. A comparative analysis of the obtained results with theoretical data is carried out. Keywords: three-layer structure, striker, bearing layer, fiberglass, impact loading. [email protected]

Modeling of Sleeved Taylor Impact Specimens

2003 ◽  
Author(s):  
William Keith Rule
Keyword(s):  
Stress State ◽  
Impact Test ◽  
Sliding Friction ◽  
Experimental Studies ◽  
Impact Testing ◽  
Strength Model ◽  
The Core ◽  
Post Test ◽  
Taylor Impact ◽  
Sliding Friction Coefficient

Recently experimental studies have been conducted using a novel form of the Taylor impact test consisting of sleeved cylinders. A soft material of known properties (OFHC Cu) was used for the core and the tight fitting sleeve was fabricated from the material of interest (AF1410 steel). On impact the mushrooming and sliding core places the sleeve in a stress state not normally found in Taylor impact testing. This paper describes a study conducted to evaluate the feasibility of backing out Johnson-Cook strength model coefficients from measured (post-test) deformed geometries of sleeved specimens using an explicit impact code (EPIC). In addition, modifications to the sleeved concept geometry (tapered and capped core) are also explored numerically as well as the sleeve/core sliding friction coefficient.

Manipulation of Germanium Nanocrystals in a Tri-Layer Insulator Structure of a Metal-Insulator-Semiconductor Memory Device

2002 ◽  
Vol 728 ◽  
Author(s):  
L.W. Teo ◽  
C.L. Heng ◽  
V. Ho ◽  
M. Tay ◽  
W.K. Choi ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Oxide Layer ◽  
Layer Structure ◽  
Charge Trapping ◽  
Middle Layer ◽  
Memory Device ◽  
Metal Insulator ◽  
Metal Insulator Semiconductor ◽  
20 Nm ◽  
Ge Nanocrystals

AbstractA metal-insulator-semiconductor (MIS) device that consists of germanium (Ge) nanocrystals embedded in a novel tri-layer insulator structure is proposed for memory applications [1]. The tri-layer structure comprises a thin (≈5nm) rapid thermal oxidation (RTO) silicon dioxide (SiO2) layer, a Ge+SiO2 middle layer (6 - 20 nm) deposited by RF co-sputtering technique and a RF-sputtered silicon dioxide capping layer. High-resolution transmission electron microscopy (HRTEM) results show that Ge nanocrystals of sizes ranging from 6 –20 nm were found after rapid thermal annealing of the trilayer structure at 1000°C for 300s. The electrical properties of these devices have been characterized using capacitance versus voltage (C-V) measurements. A significant hysteresis was observed in the C-V curves of these devices, indicating charge trapping in the composite insulator. Comparison with devices having similar tri-layer insulator structure, but with a pure sputtered oxide middle layer (i.e. minus the Ge nanocrystals), clearly indicated that the observed charge trapping is due to the presence of the Ge nanocrystals in the middle layer. The C-V measurements of devices without the capping SiO2 layer exhibited no significant hysteresis as compared to the embedded Ge nanocrystal tri-layer devices. The HRTEM micrographs showed that the presence of the capping oxide is critical in the formation of nanocrystals for this structure. By varying the thickness of the middle layer, it was found that the maximum nanocrystal size correlates well with the middle layer thickness. This indicates that the nanocrystals are well confined by the RTO oxide layer and the capping oxide layer. In addition, Ge nanocrystals formed using a thinner middle layer were found to be relatively uniform in size and distribution. This structure, therefore, offers a possibility of fabricating memory devices with controllable Ge nanocrystals size.

Theoretical and experimental studies of stress state of hollow cylinders with annular grooves

1984 ◽  
Vol 20 (4) ◽  
pp. 313-317
Author(s):  
Yu. N. Nemish ◽  
Yu. I. Vologzhaninov ◽  
A. I. Zirka ◽  
N. M. Bloshko ◽  
D. I. Chernopiskii
Keyword(s):  
Stress State ◽  
Experimental Studies ◽  
Hollow Cylinders

scholarly journals Theoretical and Experimental Analysis of Inter-Layer Stresses in Filament-Wound Cylindrical Composite Structures

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7037
Author(s):  
Piotr Krysiak ◽  
Aleksander Błachut ◽  
Jerzy Kaleta
Keyword(s):  
Composite Structures ◽  
Layer Structure ◽  
Experimental Studies ◽  
Internal Surface ◽  
Cylindrical Sample ◽  
Calculation Model ◽  
Internal Diameter ◽  
Steel Core ◽  
Filament Wound ◽  
Filament Wound Composite

This paper analyses the issues relative to the modelling of tubular (cylindrical) composite structures. This paper aims to describe the design of a multi-layer structure of filament-wound composite pipes where, after loading, the hoop-stress distribution would be as uniform as possible. That would allow the mass of the composite to decrease while maintaining the proper mechanical strength. This publication presents the development of a calculation model dedicated to mono- and multi-layered tubular composite structures. The equations describing the stress pattern were based on the Lamé Problem, whereas to describe the modelled structures, an anisotropy coefficient was introduced and interlayer pressures values were determined. To verify the calculations, experimental studies were performed. The test specimens were fabricated by winding fibre bundles around a steel core (as rings with an internal diameter of 113 mm and a height of 30 mm). For the test, the method of pressing a conical ring into a split ring, which acts on the internal surface of the tested cylindrical sample, was selected. The operation of the test rig (test stand) was simulated using the Finite Element Method (FEM). Measurements with strain gauges were conducted during the experiments.

Sign in / Sign up

Export Citation Format

Share Document