Deformation Analysis Of Structures Research Articles

Nonlinear large deformation analysis of shells using the variational differential quadrature method based on the six-parameter shell theory

The present work is concerned with the application of the variational differential quadrature (VDQ) method (Faghih Shojaei and Ansari, 2017), in the area of computational mechanics, to the nonlinear large deformation analysis of shell-type structures. To this end, based on the six-parameter shell model, the functional of energy in quadratic form is derived based on Hamilton’s principle which is then directly discretized by the VDQ technique. The formulation of article is presented in a general form so that it can be readily used for different structures such as beams, annular plates, cylindrical shells and hemispherical shells under various loading conditions. In order to reveal the accuracy of developed solution strategy, it is tested in several popular benchmark problems for the geometric nonlinear analysis of shells. The results show that the present numerical method is capable of yielding highly accurate solution in the nonlinear large deformation analysis of shells. It is also easy to implement due to its compact and explicit matrix formulation.

Design, Optimization and Analysis of a 4-stroke Diesel Engine Piston and Piston rings using Different Materials

Modern Automobiles expect a high performance from its engines, which in turn places its requirements on the piston and cylinder components. Hence the piston has to deal with harsher, and tougher thermal and mechanical conditions. It has to undergo higher operating temperatures and pressures as well as higher speeds and at the same time keeping a check on the emissions. Pistons play a key role in increasing engine efficiency by reducing weight and frictional losses. This has made it essential to devise and search unique and creative concepts and materials for Pistons repeatedly, which offers what the engine demands. In this work Aluminium Alloy-4032 has been selected as the piston material of a 4-Stroke Diesel Engine and the piston rings are made of grey cast iron and alloy steel. Piston is designed by analytical methods taking both thermal and structural effects into consideration, then modelled on CATIA V5 and the analysis of structural deformation due to thermal stresses has been done using Finite Element Analysis of Steady State Thermal and its effect on static structure using Analysis software ANSYS

Formulation and implementation of mathematical models suitable for deformation analysis of structures

Deformation monitoring is the systematic measurement and tracking of the alteration in the shape or dimensions of an object as a result of stresses induced by applied loads. Deformation monitoring is a major component of logging measured values that may be used for further computation, deformation analysis, predictive maintenance and alarming. The main purpose of structural deformation monitoring scheme and analysis is to detect any significant movements of the structure. An effective approach is to model the structure by using well-chosen discrete points located on the surface of the structure which, when situated correctly, accurately depict the characteristics of the structure. The problem of Engineering Geodesy is the formulation of the Mathematical model that will reveal the characteristic of the structure being monitored. In this paper, the mathematical model that reveals the changes in shape of a circular reservoir structure is formulated and applied numerically. A numerical solution was carried out using the Mathematical model formulated.Keywords: Accuracy, deformation, diameter, Monitoring, Mathematical model

Intelligent 3D data extraction method for deformation analysis of composite structures

Nowadays, with the development of demand for construction, the use of composite structures in architectures become more and more popularity. How to improve the intelligent level of deformation monitoring has become one of the key problems. A detailed understanding about deformation behavior is significant for better monitoring of structures, especially in terms of accuracy and detail. The innovation of this paper focuses on that terrestrial laser scanning (TLS) measurement is adopted to investigate deformation of the composite masonry structures.In this paper, deformation segmentation and analysis of the masonry structures are investigated and the deformation tendency is compared and analyzed, based on the intelligent data extraction by window selection method, where high precision 3D laser technology provides reliable experimental data for this research. The deformation of different surfaces of a composite arch is considered and the maximum displacement distribution is analyzed through partially comparing the deformation of different epoch data.

Using Drones and 3D Modeling to Survey Tibetan Architectural Heritage: A Case Study with the Multi-Door Stupa

Tibet has an average altitude of 4900 m, a complex terrain, and unique climatic conditions. The technologies used to survey this country’s local architectural heritage must be portable, efficient, and versatile. Low-cost Unmanned Aerial Vehicles (UAVs) and Structure from Motion (SfM) algorithms can help satisfy these demands. Recent studies employing nadir images from low-cost UAVs and SfM algorithms have reported positive metric results (with centimeter-level accuracy) when modeling 2D objects (e.g., land, roofs, and facades). In Tibet, however, forming a complete 3D model of architectural heritage is highly preferable and doing so requires a camera network that can create nadir and oblique images with various baselines. This study compared the accuracies of surveying a Tibetan stupa using the UAV-SfM method compared with Ground Control Points (GCP) and Terrestrial Laser Scanning (TLS). The results indicated that the UAV-derived model is accurate enough for most surveying purposes (RMSE = 2.05 cm; 1/2000 of the stupa’s dimension). The accuracy and completeness of the 3D model allowed Historic Building Information Modeling (HBIM) and structural deformation analysis to also be undertaken. In addition, the stupa was integrated with geographic data (terrain and infrastructure) for visualization, management, and evaluation purposes at a larger scale. Considering the low cost, portability, and completeness offered by UAV and SfM, this tool offers promise for surveying Tibet’s architectural heritage.

Experiment and numerical simulations of a slug rivet installation process based on different modeling methods

Slug rivet interference-fit riveting is one of the advanced connection technologies, which has been widely applied in aerospace manufacture. In the fields of residual stress analysis, structural deformation analysis, load transfer mechanism analysis, and the assessment of the effects of process parameters on riveting quality, study accuracy needs increasingly accurate and comprehensive models. Since the simulation of riveting process is a particularly time-consuming case. The aim of this paper is to develop some appropriate FE models for the special applications with a compromise between model size, calculation time, and simulation precision. Different types of FE models have been established based on force-controlled approach and displacement-controlled approach. The comparison between different FE models is satisfactory in terms of riveting process and riveting quality control criterion. The study significantly deepens the comprehension of the slug rivet installation process. Subsequent research can select an appropriate model according to its special target. The study will pave the way for further investigations.

Analysis of Manufacturing-Induced Defects and Structural Deformations in Lithium-Ion Batteries Using Computed Tomography

Premature battery drain, swelling and fires/explosions in lithium-ion batteries have caused wide-scale customer concerns, product recalls, and huge financial losses in a wide range of products including smartphones, laptops, e-cigarettes, hoverboards, cars, and commercial aircraft. Most of these problems are caused by defects which are difficult to detect using conventional nondestructive electrical methods and disassembly-based destructive analysis. This paper develops an effective computed tomography (CT)-based nondestructive approach to assess battery quality and identify manufacturing-induced defects and structural deformations in batteries. Several unique case studies from commercial e-cigarette and smartphone applications are presented to show where CT analysis methods work.

Deformation characteristic and mechanism of blisters in cement concrete bridge deck pavement

The waterproofing membrane applied on cement concrete bridge deck usually experiences small uplift blisters, which leads to serious corrosive problems when water infiltrates into the bridge deck through the blister area. It is very important to reveal the formation and propagation of the blister for decreasing the damage of bridge deck pavement. In this paper, the environmental simulation blister test is proposed originally, and MatchID-3D (MTI-3D) structural deformation analysis system is adopted to measure the blister deformations. The deformation characteristic and mechanism of the blister are investigated. The test results show that the stages of blister deformation can be determined according to the deflection rate. The deflection deformation of the blister is a rapid process happening mainly in the third stage, while the debonding deformation is a relatively stable and long-term process. The test temperature, initial debonding aperture, and water have great influences on the failure time, meanwhile the former two factors also affect the total debonding length seriously. An improved blister test method is developed in this paper to accurately study the blister deformation under different environmental conditions, which helps to determine effective measures to eliminate the blister in bridge deck pavement.

Late Cretaceous tectono-magmatic activity in the Nize region, central Tibet: evidence for lithospheric delamination beneath the Qiangtang–Lhasa collision zone

ABSTRACTThe results of zircon U–Pb age dating and whole-rock geochemistry for the Late Cretaceous Nize granodiorite porphyries, combined with analysis of near-coeval structural deformation of the Lower Cretaceous Langshan Formation, provide new data to better understand the tectonic evolution of the northern Lhasa subterrane, central Tibet. Zircon U–Pb ages of 89.2 ± 0.3 Ma to 87.8 ± 0.3 Ma indicate emplacement during the Late Cretaceous. Granodiorite porphyry intrusions were contemporaneous with the development of a regional angular unconformity, overlain by the Upper Cretaceous Jingzhushan (or Abushan) Formation, within the collision zone between the South Qiangtang and Lhasa terranes. Geochemical data for Nize granodiorite porphyries indicate that they have a calc-alkaline composition enriched in large-ion lithophile elements and light rare earth elements and depleted in high-field-strength elements and heavy rare earth elements. High Al2O3 and Sr contents, low Yb and Y contents, and high Sr/Y ratios are similar to adakitic magmas.Structural analysis indicates two stages of deformation (D1 and D2), with D1 forming the focus of the present study. The D1 deformation is represented by large-scale faults and records two periods of faulting. These periods are recognized as early compressional thrust faulting and a dominant late stage characterized by normal faulting and extension, with the latter stages of D1 being near-coeval with the emplacement of the Nize granodiorite porphyries. The combination of zircon ages, geochemical data, and structural analysis indicates that the Nize granodiorite porphyries formed after collision of the South Qiangtang and Lhasa terranes. Adakitic magma derived from partial melting of the thickened lower or middle crust resulted from lithospheric delamination that may have been promoted by the convective removal of deeper lithospheric mantle.

Numerical and Empirical Simulation of Linear Elastic Seismic Response of a Building: The Case of Nice Prefecture

The structural motion of a tall reinforced concrete (RC) building on alluvial soil in Nice (France) is continuously recorded using accelerometers. The structural behavior of the building is studied using operational modal analysis (OMA) to identify its dynamic properties, a finite element (FE) model to reproduce the building response, and empirical Green's functions (EGFs) to generate the structural response to ground motions stronger than those registered in the analyzed seismic area. These different approaches are applied for the analysis of seismic response of the instrumented building and results are consistent. The FE model is calibrated by comparing natural frequencies and mode shapes with those obtained using OMA. Numerically-simulated time histories are qualitatively and quantitatively compared with recordings showing good agreement. Based on regional earthquakes, linear seismic response of the building is simulated for a stronger scenario earthquake using EGF. This approach allows for structural deformation analysis of existing buildings without the need of structural plans and mechanical parameter calibration in the case where the seismic response is within linear elastic regime.

Deformation monitoring of typical composite structures based on terrestrial laser scanning technology

Terrestrial laser scanning (TLS) technology plays an important role in the field of deformation monitoring nowadays, and a lot of the architectures are arched composite structures, which are required to be further understood for their mechanical and physical properties. Only a theoretical numerical analysis is sometimes difficult and defective to achieve, due to varying loads and other factors influencing the stability and reliability of such structures. Therefore, measurements can improve the theoretical analysis in several ways. One of the most important issues is the deformation analysis within load experiments.This paper focuses on the presentation of new possibilities for surface-based measurement techniques and their applicability in the deformation analysis of arched structures. The goal of this paper is to investigate the difference of load-displacement relationships between arched and beam structures though a static load experiment based on high accuracy TLS measurement techniques and the surface analysis method. In this paper, we try to reveal the influencing mechanism of ‘prestressing-like’ force and interpret why arched structures can withstand a surprisingly greater load than beam structures under the same conditions.

TLS-based composite structure deformation analysis validated with laser tracker

This paper focuses on the adjustment of B-spline approximation to terrestrial laser scanning (TLS) data and its contribution to deformation analysis of composite arched structures. The deformation of an arch structure under static loading conditions are investigated with TLS technology which is accurate, time-efficient, and capable to obtain dense 3D coordinates of point clouds for the measured objects.Highly accurate approximation methods for the point clouds data are extremely important for structural deformation analysis. The innovation of this paper is that parameters of B-spline is optimized with laser tracker (LT) to improve the accuracy of deformation monitoring and analysis, where the result is justified with LT data and the uncertainties are analyzed. It is revealed that optimized B-spline approximation agrees better with LT result. The improvement to the B-spline curve with minimum standard deviation reaches 52%, and its improvement to polynomial approximation reaches 77%.

A feature extraction method for deformation analysis of large-scale composite structures based on TLS measurement

How to obtain a three-dimensional (3D) model efficiently and extract the feature information of larger-scale composite structures, such as tunnels, accurately is a significant issue in the field of health monitoring. Therefore, an effective method based on TLS measurement is proposed and developed using surface-based non-destructive technology.In this paper, terrestrial laser scanning (TLS) technology is adopted to investigate the tunnel structure, focusing on the extraction of the characteristic section and central curve, which could be applied in deformation monitoring. Point cloud data from TLS measurement is processed in four steps: section extraction, section projection, calculation of central points and curve approximation.The innovation of this paper lies in the projection and iterative filtering of the ring data and rasterization of the point clouds for vertical and horizontal lines. The random sample consensus (RANSAC) algorithm is implemented to approximate the vertical and horizontal lines. The central curve, approximated from the central points, agrees with the general design model and the accuracy falls within the millimeter range.

Short-Circuit Strength of Power Transformer Windings-Verification of Tests by a Finite Element Analysis-Based Model

A test stand to evaluate the radial buckling strength of power transformer windings under the influence of electromagnetic forces is presented. The resulting conductor deformation can be measured in parallel to the sinusoidal test current. The proposed test results focus on the inception of forced buckling for continuously transposed conductors (CTCs), which are a special type of conductor often used in power transformer windings. In the literature, there barely exist calculations to the radial buckling withstand capability of CTCs. Therefore, a finite-element analysis-based simulation model for this kind of conductor is proposed and verified by the tests. For this verification, three different CTC types are used. The final simulation model is based on a coupled analysis of magnetostatic force calculation and static structural deformation analysis. It suitably reproduces the measurement results from the dynamic short-circuit tests. Furthermore, a standard formula describing radial buckling phenomena inside power transformers is adapted for use with CTCs.

Gondwana-Derived Terranes Structural Mapping Using PALSAR Remote Sensing Data

Gondwana-derived terranes are now separated by major faults or suture zone, which are rarely simple and easily recognizable lineaments. Different association of ore mineral systems such as deposits of sediment-hosted/orogenic gold and granite-related minerals is discovered in collision and subduction zones of the Gondwana-derived terranes. They are associated with large-scale, terrane-bounding fault systems and broad areas of deformation. Mineralization mostly associated with structurally-controlled complex lodes, veins, sheeted veins and veinlets in diverse orientations. Recognizing the structural significance of lineaments and curvilinear is very difficult in tropical, arid and Antarctic regions due to environmental obstacles. Remote sensing data could be used to detect geological structures associated with suture zones between Gondwana-derived terranes especially for large inaccessible regions where fieldwork is limited or nonexistent. In this investigation, the Phased Array type L-band Synthetic Aperture Radar (PALSAR) satellite remote sensing data were used to map major geological structures in the Bentong-Raub Suture Zone of Peninsular Malaysia. It is one of the major structural zones in Sundaland, Southeast Asia, which forms the boundary between the Gondwana-derived the Sibumasu terrane and Sukhothai-Indochina arc. Structural features associated with sediment-hosted/orogenic gold deposits in the Central Gold Belt and tin mineralization in S-type granites in the Main Range were investigated using PALSAR data and comprehensive fieldwork. Results indicate that main faults strike along 340° to 350° that are intersected by many shear or lateral fault zones are high potential zone for gold mineralization in the Central Gold Belt. Hydrothermally alteration mineral zones and cataclastic rocks are also the other indicators of gold mineralized veins in the gold belt. High potential zones for tin mineralization are N–S strike-slip faults, fault zones and shear zones trending E–W, NE–SW and WNW–ESE in dissected crystalline granitic rocks that are associated with hydrothermal alteration zones in the Western Tin Belt. Lineament analysis using PALSAR satellite remote sensing data is a useful tool for mapping major geological structural features and detection of the boundary between the Gondwana-derived terranes and detailed structural analysis of fault systems and deformation with high potential for a variety of mineral resources, especially in tropical, arid and Antarctic regions.

Structural Analysis of Plastic Deformation around the Crack Initiated in Austenitic Stainless Steel

Metallic implants should have the following basic characteristics as excellent biocompatibility, high corrosion resistance, suitable mechanical properties (strength, fracture toughness...) and high wear resistance in order to serve safely and adequately for a long-time period without rejection. Austenitic stainless steels are popular for implant applications because of their availability, lower cost, excellent fabrication properties, accepted biocompatibility and toughness. The mechanical working conditions within human body are tough, because surgical implants are subjected to static and dynamic mechanical loading and exposed to surrounding aggressive environment such as human body. As the material is subjected to cyclic loading, micro-plastic deformation occurs around the crack [1,2]. The aim of this paper is to observe the area around the originated crack on the testing bar. The microstructural analysis of initial state and after three-point bending was performed by optical and scanning electron microscopy. Hardness measurement was performed under the crack originated after cyclic loading.

Deformation analysis of compound structures under electromagnetic press-molding

Deformation analysis of compound structures under electromagnetic press-molding

Buoyancy coupling with structural deformation analysis of ship based on finite element method

The hydrostatic balance of a ship floating on the water is the result of buoyancy coupling with structural deformation. As to the ship with a relatively flexible hull girder, this coupling phenomenon is very important for the accuracy of general design and structural analysis. However, the existing ship design methods could not solve this coupling problem accurately. Aiming at this problem, a new numerical method based on FEM, called Buoyancy Coupling with structural Deformation Analysis (BCDA), is presented in this paper to improve both efficiency and accuracy of ship design. In BCDA, the concept of buoyancy element is proposed to simulate element on hull wet surface. As to a buoyancy element, the buoyant force is regarded as properties of element rather than external load. The buoyant matrices for both quadrilateral and triangular elements are derived, and the structural stiffness matrix of buoyant element is corrected by buoyant matrix. Being different from the traditional FEM, constraints on translation freedom along vertical direction should not be added in BCDA. The generalized displacements for each node, which consist of displacements due to buoyancy change and structure elastic deformations, are obtained by solving the global equilibrium equations. The results of BCDA satisfy both structural mechanics equation and gravity-buoyancy balance equation. A 15,000t launching barge is taken as example to verify the validity and accuracy of BCDA. With this example, it also proved that the coupling analysis of buoyancy and hull structural deformation is necessary for the general design and structural analysis of floating structure with relatively flexible hull.

A new twelve-parameter spectral/hp shell finite element for large deformation analysis of composite shells

In this paper, a new 12-parameter shell finite element for large deformation analysis of composite shell structures is developed using third-order thickness stretch kinematics. The continuum shell element is utilized in the numerical simulations of laminated composite and functionally graded materials, using a high-order spectral/hp approximations. The results obtained from the 12-parameter shell element are compared with those obtained from the 7-parameter shell element to bring out the differences. Deflections and maximum stresses are computed using the two models. The results show that the responses predicted by the two formulations (and models) are consistent with each other, with the 12-parameter model showing slight difference from those predicted by the 7-parameter model.

LAKE URMIA BRIDGE STABILITY ASSESSMENT: RESULTS FROM TERRASAR-X SPOTLIGHT MODE IMAGES

Abstract. In this study we investigate stability of Lake Urmia bridge, locally also known as Shahid Kalantari’s highway bridge, in northwest of Iran using high-resolution satellite radar imagery. The radar dataset includes 22 SAR images acquired in SpotLight mode from 2014 to 2015 in an ascending orbit by TerraSAR-X satellite. A high-resolution Digital Elevation Model (DEM) of the area was constructed from a pair of TanDEM-X bi-static data on June 2012 to remove the effect of topography from interferometry observations. The analysis of X-band interferograms shows high number of displacement fringes, which are interpreted as being caused by thermal dilation due to temperature differences in the imaged area between two SAR acquisitions. This effect, which can often be observed in single interferograms, have important impact on time-series products and should be considered for deformation analysis of bridge structures.