Numerička analiza utjecaja vrste tla na vibracije tračnica

master's thesis

• Title (english): Numerical analysis of the influence of soil type on rail vibrations
• Author: Iva Žmegač
• Mentor: Lana Virag (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2024-12-05, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

Željeznica se prepoznaje kao ekološki prihvatljiv oblik prijevoza koji smanjuje prometne gužve, emisiju stakleničkih plinova i zagađenje zraka. U sklopu europskog zelenog plana i Strategije za održivu i pametnu mobilnost, Europska unija nastoji povećati udio željezničkog prometa, posebice u segmentima velike brzine i teretnog prijevoza. Godina 2021. proglašena je Europskom godinom željeznice kako bi se dodatno promovirale prednosti ovog oblika transporta. Međutim, željeznica ima izazove poput buke i vibracija koje utječu na okoliš, ljudsku kvalitetu života i osjetljive strojeve u objektima poput bolnica ili industrijskih postrojenja.
Rad analizira prijenos vibracija koje nastaju tijekom vožnje vlakova kroz različite vrste tla te istražuje kako ta svojstva tla utječu na širenje vibracija. Korištenjem numeričkih metoda, odnosno metode konačnih elemenata, u softveru ABAQUS izrađen je pojednostavljeni 3D model željezničkih tračnica i slojeva tla. Analiza je uključila statičke i dinamičke deformacije tla pri različitim vrstama vlakova i njihovim brzinama. Utvrđeno je da tla s manjim modulom elastičnosti, poput gline, proizvode veće pomake i naprezanja, dok šljunkovita tla pokazuju veću otpornost na vibracije.
Poseban naglasak stavljen je na izbjegavanje rezonantnih frekvencija i prilagođavanje svojstava tla ispod pruga, što doprinosi smanjenju vibracija. Praktična rješenja uključuju pojačavanje krutosti tla, dodatak elastičnih elemenata ili primjenu višeslojnih sustava koji kombiniraju stabilnost i smanjenje vibracija. Numerički modeli, kao što su beskonačni elementi, omogućuju preciznu simulaciju neograničenog tla te bolji uvid u interakciju tla i strukture.
Ograničenja ovog rada uključuju pojednostavljeni model bez složenosti poput heterogenih svojstava tla i nelinearnih efekata te izostanak validacije kroz terenska mjerenja. Unatoč tome, rezultati pružaju temelj za buduće istraživanje i smjernice za dizajn sustava željeznice otpornijih na vibracijske učinke. Rad ističe potrebu za pažljivim projektiranjem slojeva tla i temelja kao ključnog faktora u smanjenju negativnih utjecaja željezničkog prometa.

Abstract (english)

Railways are recognized as an environmentally friendly mode of transportation that reduces traffic congestion, greenhouse gas emissions, and air pollution. As part of the European Green Deal and the Sustainable and Smart Mobility Strategy, the European Union aims to increase the share of rail traffic, particularly in the segments of high-speed and freight transport. The year 2021 was declared the European Year of Rail to further promote the advantages of this mode of transport. However, railways face challenges such as noise and vibrations that affect the environment, human quality of life, and sensitive machinery in facilities like hospitals or industrial plants.
This study analyzes the transmission of vibrations generated during train travel through different soil types and investigates how these soil properties influence the propagation of vibrations. Using numerical methods, such as the finite element method (FEM), a simplified 3D model of railway tracks and soil layers was developed in the ABAQUS software. The analysis included static and dynamic deformations of the soil under various types of trains and their speeds. It was found that soils with lower elasticity modulus, such as clay, produce greater displacements and stresses, while gravelly soils demonstrate higher resistance to vibrations.
Special emphasis is placed on avoiding resonant frequencies and adjusting soil properties beneath tracks, which contributes to vibration reduction. Practical solutions include increasing soil stiffness, adding elastic elements, or implementing multilayer systems that combine stability and vibration mitigation. Numerical models, such as infinite elements, enable precise simulations of unbounded soil and provide better insights into soil-structure interaction.
The limitations of this study include a simplified model that does not account for complexities such as heterogeneous soil properties and nonlinear deformation effects, as well as the absence of validation through field measurements. Despite these limitations, the results provide a foundation for future research and guidelines for designing railway systems more resilient to vibration effects. The study highlights the need for careful design of soil layers and foundations as a key factor in minimizing the negative impacts of railway traffic.

• Keywords: željeznica; tračnice; numerička analiza; vibracije; buka; beskonačni elementi; tlo
• Keywords (english): railway; tracks; numerical analysis; vibrations; noise; infinite elements; soil
• Language: croatian
• URN:NBN: urn:nbn:hr:235:389937
• Study programme: Title: Mechanical Engineering; specializations in: Design, Process and Energy Engineering, Production Engineering, Engineering Modelling and Computer Simulation, Marine Engineering, Industrial Engineering and Management, Materials Engineering, Mechanics and Robotics, Autonomous Systems, Mechatronics and Robotics; Course: Autonomous Systems; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra inženjer/inženjerka strojarstva (sveučilišni/a magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-12-01 17:00:38