Papers by Keyword: Structural Analysis

Abstract: The mechanical properties of joined structures are determined considerably by the chosen joining technology. With the aim of providing a method that enables a faster and more profound decision-making in the spatial distribution of joining points during product development, a new method for the load path analysis of joining points is presented. For an exemplary car body, the load type in the joining elements, i.e. pure tensile, shear and combined tensile-shear loads, is determined using finite element analysis (FEA). Based on the evaluated loads, the resulting load paths in selected joining points are analyzed using a 2D FE-model of a clinching point. State of the art methods for load path analysis are dependent on the selected coordinate system or the existing stress state. Thus, a general statement about the load transmission path is not possible at this time. Here, a novel method for the analysis of load paths is used, which is independent of the alignment of the analyzed geometry. The basic assumption of the new load path analysis method was confirmed by using a simple specimen with a square hole in different orientations. The results presented here show a possibility to display the load transmission path invariantly. In further steps, the method will be extended for 3D analysis and the investigation of more complex assemblies. The primary goal of this methodical approach is an even load distribution over the joining elements and the component. This will provide a basis for future design approaches aimed at reducing the number of joining elements in joined structures.

Abstract: A brake disc has an significant role in the vehicle and it is used to stop or decrease the velocity of the vehicle. The demand of metal matrix composites (MMCs) is greatly increased in fabricating the brake disc since it possesses a low density and high thermal conductivity. Over-heating will lead to the malfunction of the braking system and affect the safety of vehicle. Reduced weight of brake disc can decrease the use of fuel of the vehicle thus improve the fuel usage efficiency. This paper is focussed to determine the suitability of AlSiCGr hybrid MMCs compared to cast iron in terms of thermal and structural properties for brake disc. Both design of brake discs was proposed and modelled using CATIA and then imported to ANSYS software for structural and thermal analysis. The simulation results showed that AlSiCGr hybrid MMCs brake disc has higher thermal and structural performance compared to the original cast iron brake disc.

Abstract: A material (polymer + glass fibers) is characterized by its inhomogeneity and anisotropy. This material is subjected an injection molding simulation at first (generally unnewton type of fluid). Then the material is cooled and common structural analysis (static, dynamic and thermal) is performed. The cooled material has dissimilar mechanical properties for each of discrete element. Thus the mechanical properties (after simulation of load) will completely have different values when influence of injection molding is included.

Abstract: The paper deals with the analysis of mechanical properties of welded joints made of AW 2099 aluminium-lithium alloy by electron beam welding. The thickness of the experimental material was 3±0.2 mm. PZ EZ 30 STU electron beam welding machine was used for production of welds. Maximum accelerating voltage used within this study was 55 kV. Metallographic analysis, hardness measurement test and static tensile were carried out. The structure of the weld joint of aluminium-lithium alloy was investigated. Produced welded joints were characterized by the presence of following zones: heat affected zone (HAZ), equiaxed non-dendritic zone (EQZ), columnar dendritic zone (CDZ) and equiaxed dendritic zone (EDZ). EQZ grains were formed due to heterogeneous nucleation on precipitates at the fusion boundary. EQZ is typical for joining of aluminium lithium alloys.

Abstract: This paper presents the method of establishing artificial accelerogram for analysis and calculation of structures in accordance with seismic characteristics and earthquake risk in one specific construction areas in Vietnam. The artificial accelerogram allow to analyze nonlinear or linear dynamic behavior of the structures in time series in accordance with Vietnam National Standards for Design of structures for earthquake resistances (TCVN 9386: 2012) and seismic parameters specified in Vietnam Building Code on Natural Physical and Climatic Data for Construction (QCVN 02:2009-BXD). The accelerograms are also used as input parameters for shaking table tests by Vietnam's most modern sharking table at the Vietnam Institute for Building Science and Technology.

Abstract: This paper illustrates the results of the activities of analysis and structural assessment of the Assumption of the Virgin Mary chapel, in Prague. The chapel, an oval-shaped building covered with a dome, was built at the end 16th century and can be considered the last example of renaissance architecture and at the same time the first example of baroque architecture in Prague: it is a significant testimony of the close connection between local artists and their Italian teachers. The building closed to visitors during the last decades for the presence of some structural damages and because severely degraded due to lack of maintenance, was reopened in the 2017 after a notable restoration process. This paper gives attention to the interdisciplinary approach used to diagnosis and structural assessment of the chapel, based on the activities of the “knowledge path,” the subsequent structural analysis and the intervention design. Particular attention was paid to the contribution of the historical review, geometric laser scanner survey and mechanical characterization of the structural materials. All these steps result necessary to identify potential vulnerabilities and to enable the understanding of the effective structural models, also in view of proposing adequate retrofit solutions. A numerical model of the chapel was prepared and calibrated. Finally, the structural assessment for the vertical and seismic loading was performed.

Abstract: In this study, a novel numerical method to analyze the bifurcation problemof a rate dependent material using the finite element method is proposed. The consistent stiffness matrix, which is required for a bifurcation analysis using the finite element method, for a rate dependent material is generally hard to compute, therefore, a computational method to calculate the tangent stiffness matrix based on a numerical differential is introduced so that exact bifurcation analyses for the rate dependent material can be conducted. A numerical example of the proposed method is demonstrated, and the adequacy of the proposed method is discussed.

Abstract: In this paper, we propose an indicator to systems-of-systems (SoS) structural analysis through dependencies evaluation which is based on interoperability and exchange inefficiency assessments, with dependencies representing links between component systems within the SoS. Interoperability is a quality that can be viewed from various perspectives. Therefore, we propose an illustrative classification for interoperability that embraces: barriers, scopes and levels. Our study involves a set of metrics to assess each interdependency’s interoperability barriers within the SoS through interoperability levels. Two different case studies, from the Moroccan economic infrastructure, are presented to apply the proposed approach. Results are cross-compared and evaluated.

Abstract: Railway and highway subgrade is considered to be one of the most vulnerable elements of transport structures. Undoubtedly, its failure may cause serious delays or even traffic interruption. Moreover, subgrade reliability is affected by various material, technological, climatic, as well as, soil-related and geological factors. This paper presents the results of a structural analysis with impact matrix cross-reference multiplication applied to a classification (MICMAC) technique applied for the identification of the most essential factors based on the intensity of their influence on each other. By doing so, an opinion survey was undertaken through expert consultations with industry and academic representatives in the field of construction materials, design, construction and operation of railways and roads in order to increase the subgrade effectiveness and reliability. Based on the outcomes of the derived structural analysis, it can be concluded that the following factors are the most influential: strength, water and physical properties of the top subgrade layer material; optimal subgrade soil moisture monitoring during its maintenance; and construction management of subgrade. Targeted control of the mentioned factors in general, and the top subgrade layer properties in particular, mainly depends on the properties of applied materials. This condition is generic, regardless of a region where railways and roads are being operated.

Abstract: A reasonably accurate, low-cost system for the monitoring of strains in simple physical models within the field of Structural Engineering, based on Internet of Things, is presented, calibrated and discussed. The system only requires average, economic devices as Arduino microcontroller and strain gauges. Several tests on a case study of a scaled-cantilevered aluminium beam with different loading are conducted. Governing parameters are calibrated aimed at an optimization when benchmarked against theoretical and experimental results obtained with a reference device. Results show great accuracy; however, the need of setting of the parameters campaign-by-campaign, especially aimed at dealing with thermal drift, becomes a shortcoming. Still, its minimum cost and user-friendly management makes it a suitable solution for different applications.