A New Non-Destructive Testing Method Used in the Axle of Landing Gear

2011 ◽  
Vol 80-81 ◽  
pp. 1150-1154
Author(s):  
Qing Song Tu ◽  
Wei Min Zhang ◽  
Li Huang ◽  
Cheng Feng Chen ◽  
Qiu Yong
Keyword(s):  
Stress Concentration ◽  
Damage Zone ◽  
Bending Moment ◽  
Landing Gear ◽  
Magnetic Memory ◽  
Destructive Testing ◽  
Main Bearing ◽  
Structural Part ◽  
Testing Method ◽  
Structural Parts

The relations between stresses and leakage magnetic signal of concentration area of the airplane’s landing gear under varying load were studied. The finite element method was used to calculate the stress of axle under different conditions; An experiment was designed to simulate the stress status under the bending moment, the slight magnetic signals on specimen were measured, and the relation of the signals and stress was studied. The new testing method was explained with the theory of ferromagnetic and the significance of this technique for detecting defects of the airplane structural part was discussed. The safety of airplane’s main bearing parts plays an important role during its operation and it often comes to bad situation of fatigue damage for stress concentration [1, 2]. To prevent the breaking down of structural parts and get rid of big accidents, it becomes important and necessary to find out the early concentration and damage zone, and to make some certain examination of damage and stress status [3]. The method of magnetic memory testing would be effective for the confirming of stress concentration zone in the equipment or structural parts, and could lead the way ahead the matters of fatigue analysis, evaluation of equipment life and technological design. The method can detect the endurance failure of the airplane’s undercarriage shaft, which is composed of ferromagnetic materials, and that provides the experimental basis for the prevention of parts’ fatigue defects.

Non-Contact Measurement of Residual Magnetization Caused by Plastic Deformation of Steel

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Aroba Saleem ◽  
P. Ross Underhill ◽  
Thomas W. Krause
Keyword(s):  
Plastic Deformation ◽  
Stress Concentration ◽  
Oil And Gas ◽  
Magnetic Measurements ◽  
Magnetic Domain ◽  
Residual Magnetization ◽  
Magnetic Memory ◽  
Buried Pipe ◽  
Destructive Testing ◽  
Primary Means

Abstract Pipelines are the primary means of land transportation of oil and gas globally, and pipeline integrity is, therefore, of high importance. Failures in pipelines may occur due to internal and external stresses that produce stress concentration zones, which may cause failure by stress corrosion cracking. Early detection of stress concentration zones could facilitate the identification of potential failure sites. Conventional non-destructive testing (NDT) methods, such as magnetic flux leakage, have been used to detect defects in pipelines; however, these methods cannot be effectively used to detect zones of stress concentration. In addition, these methods require direct contact, with access to the buried pipe. Metal magnetic memory (MMM) is an emerging technology, which has the potential to characterize the stress state of underground pipelines from above ground. The present paper describes magnetic measurements performed on steel components, such as bars and tubes, which have undergone changing stress conditions. It was observed that plastic deformation resulted in the modification of measured residual magnetization in steels. In addition, an exponential decrease in signal with the distance of the sensor from the sample was observed. Results are attributed to changes in the local magnetic domain structure in the presence of stress but in the absence of an applied field.

Application Study of Metal Magnetic Memory Testing in the Q345E Steel Weld Inspection

2013 ◽  
Vol 273 ◽  
pp. 609-613
Author(s):  
Peng Lin Zhang ◽  
Wen Ke Wang ◽  
Yan Ping Wang ◽  
Li Cao
Keyword(s):  
Stress Concentration ◽  
Close Relation ◽  
Magnetic Memory ◽  
Memory Testing ◽  
Metal Magnetic Memory ◽  
Application Study ◽  
Testing Method ◽  
Weld Inspection ◽  
Nondestructive Testing Method ◽  
Metal Magnetic Memory Testing

Metal magnetic memory testing is a new nondestructive testing method and used to diagnose ferromagnetic components stress concentration. Welding defects and stress concentration has the close relation. This paper used metal magnetic memory in the weld inspection to study an effective weld magnetic memory testing method, at the same time to verify the results by X-ray inspection.

A Novel Three-Dimensional Non-Contact Magnetic Stress Inspection Technology and its Application on LNG Pipeline

2020 ◽  
Author(s):  
Guoxi He ◽  
Tengjiao He ◽  
Kexi Liao ◽  
Hongdong Zhu ◽  
Shuai Zhao
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Metal Loss ◽  
Magnetic Memory ◽  
Destructive Testing ◽  
Inspection Method ◽  
Precise Position ◽  
Testing Technology ◽  
Relative Stress ◽  
Transmission Pipeline

Abstract On the basis of the metal-magnetic-memory (MMM) effect, a three-dimensional high-precision non-contact pipeline magnetism-based stress inspection (PMSI) technology is developed for trenchless inspection of buried pipeline defects. This technology is a new non-destructive testing technology, which can find the possible stress concentration area (SCA) along the buried gas transmission pipeline. Hence, we could further judge according to the testing data that the stress concentration is caused by the overpressure which results from whether the pipeline external load at the potential landslide of the soil or serious metal loss such as corrosion defects. The stress inspection method determines the relative risk of defects by directly quantifying the change level of stress, rather than calculating the geometric parameters (length, width, height) of defects. The PMSI was carried out on a 10.3 km LNG pipeline and two level-II SCAs were found. A comprehensive index F was defined to evaluate the severity quantitatively and judge the grade of the defect status as well as the sensitive. Thus, the relative stress and thereby the safety state of the pipeline are judged, and then the precise position of the relatively serious section on the pipeline is determined.

Dynamics of the macromolecular composition of the biomass of microalgae in the morning under natural light. Model

2020 ◽  
pp. 45-52
Author(s):  
Alexander S. Lelekov ◽  
Anton V. Shiryaev
Keyword(s):  
Biochemical Composition ◽  
Initial Conditions ◽  
Natural Light ◽  
Photoautotrophic Growth ◽  
Structural Part ◽  
Basic Model ◽  
Microalgae Culture ◽  
Simulation Results ◽  
Structural Parts ◽  
Macromolecular Composition

The work is devoted to modeling the growth of optically dense microalgae cultures in natural light. The basic model is based on the idea of the two-stage photoautotrophic growth of microalgae. It is shown that the increase in the intensity of sunlight in the first half of the day can be described by a linear equation. Analytical equations for the growth of biomass of microalgae and its macromolecular components are obtained. As the initial conditions, it is assumed that at the time of sunrise, the concentration of reserve biomass compounds is zero. The simulation results show that after sunrise, the growth of the microalgae culture is due only to an increase in the reserve part of the biomass, while the structural part practically does not change over six hours. Changes in the ratio of the reserve and structural parts of the biomass indicate a change in the biochemical composition of cells.

The Influence of Loads Superposition, Deterioration Due to Cracks and Residual Stresses on the Strength of Tubular Junction

2017 ◽  
Vol 68 (6) ◽  
pp. 1267-1273
Author(s):  
Valeriu V. Jinescu ◽  
Angela Chelu ◽  
Gheorghe Zecheru ◽  
Alexandru Pupazescu ◽  
Teodor Sima ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Residual Stresses ◽  
Bending Moment ◽  
Combined Loading ◽  
Torsional Moment ◽  
Calculation Methods ◽  
State Of Stress ◽  
Cracked Structures ◽  
Total Participation ◽  
Theoretical Results

In the paper the interaction of several loads like pressure, axial force, bending moment and torsional moment are analyzed, taking into account the deterioration due to cracks and the influence of residual stresses. A nonlinear, power law, of structure material is considered. General relationships for total participation of specific energies introduced in the structure by the loads, as well as for the critical participation have been proposed. On these bases: - a new strength calculation methods was developed; � strength of tubular cracked structures and of cracked tubular junction subjected to combined loading and strength were analyzed. Relationships for critical state have been proposed, based on dimensionless variables. These theoretical results fit with experimental date reported in literature. On the other side stress concentration coefficients were defined. Our one experiments onto a model of a pipe with two opposite nozzles have been achieved. Near one of the nozzles is a crack on the run pipe. Trough the experiments the state of stress have been obtained near the tubular junction, near the tip of the crack and far from the stress concentration points. On this basis the stress concentration coefficients were calculated.

scholarly journals Towards Efficient Milling of Multi-Cavity Aeronautical Structural Parts Considering ACO-Based Optimal Tool Feed Position and Path

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 88
Author(s):  
Yupeng Xin ◽  
Yuanheng Li ◽  
Wenhui Li ◽  
Gangfeng Wang
Keyword(s):  
High Speed ◽  
Tool Path ◽  
Milling Process ◽  
Ant Colony ◽  
Machining Accuracy ◽  
Ant Colony Optimization Algorithm ◽  
Peripheral Milling ◽  
Structural Part ◽  
Milling Method ◽  
Structural Parts

Cavities are typical features in aeronautical structural parts and molds. For high-speed milling of multi-cavity parts, a reasonable processing sequence planning can significantly affect the machining accuracy and efficiency. This paper proposes an improved continuous peripheral milling method for multi-cavity based on ant colony optimization algorithm (ACO). Firstly, by analyzing the mathematical model of cavity corner milling process, the geometric center of the corner is selected as the initial tool feed position. Subsequently, the tool path is globally optimized through ant colony dissemination and pheromone perception for path solution of multi-cavity milling. With the advantages of ant colony parallel search and pheromone positive feedback, the searching efficiency of the global shortest processing path is effectively improved. Finally, the milling programming of an aeronautical structural part is taken as a sample to verify the effectiveness of the proposed methodology. Compared with zigzag milling and genetic algorithm (GA)-based peripheral milling modes in the computer aided manufacturing (CAM) software, the results show that the ACO-based methodology can shorten the milling time of a sample part by more than 13%.

Modelling and Analysis of Integrated Hotforming and Quenching Processes

2005 ◽  
Vol 6-8 ◽  
pp. 787-794 ◽  
Author(s):  
D. Lorenz ◽  
Karl Roll
Keyword(s):  
Lightweight Design ◽  
Experimental Investigations ◽  
Boron Steel ◽  
General Tendency ◽  
The Finite Element Method ◽  
Contact Heat ◽  
Simulation Accuracy ◽  
Structural Part ◽  
Component Strength ◽  
Structural Parts

In the automotive industry a general tendency to choose steels with enhanced strength for structural parts can be observed. This trend results from the increased lightweight design efforts to satisfy the fleet consumption restrictions. Hot forming and quenching of boron steel offers the possibility to improve the component strength and reduce the weight of structural parts. The main influences on the process are described and a method to model and simulate this process using the finite element method using LS-DYNA is presented. Experimental investigations of the contact heat transfer have been carried out to enhance the simulation accuracy. A prototyping tool of a structural part is used to examine the process under production conditions. Temperatures of the tool and the part are measured during the process. These temperatures are compared with the simulation results in order to reevaluate the results of the process simulation.

Elasto-Plastic Stress Distribution in Triplate Joint Assembly under Bending Moment

2007 ◽  
Vol 345-346 ◽  
pp. 1437-1440
Author(s):  
Tae Hyun Baek ◽  
Seung Kee Koh ◽  
Jie Cheng
Keyword(s):  
Finite Element Method ◽  
Residual Stresses ◽  
Pure Aluminum ◽  
Main Tool ◽  
Bending Moment ◽  
The Finite Element Method ◽  
Shipbuilding Industry ◽  
Structural Parts ◽  
Von Mises

Pre-produced triplate transition joint assemblies are widely used in shipbuilding industry to make welds between aluminum and steel for a number of years now. The straight-shaped transition joint assemblies are bent during shipbuilding. So it is necessary to study the residual stresses created by punch forming, which would have heavy effects on the quality of structural parts. ABAQUS is a suite of powerful engineering simulation programs, based on the finite element method. In this paper, ABAQUS was used as the main tool to simulate the residual stresses in a triplate transition joint after unloading. Punch-pressing was carried to simulate bending moment in ABAQUS. The triplate is consisted of baselayer (steel: Lloyd’s Shipplate Gr. A), interlayer (pure aluminum: Al99.5) and superlayer (Al-Mg alloy: AlMg4.5Mn). Results from the ABAQUS analysis showed that increasing the radius of punch significantly reduced the von Mises residual stresses in steel. Changes of von Mises residual stresses in interlayer (Al99.5) and superlayer (AlMg4.5Mn) were negligible.

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