Rijitlik Kütle Dağılımı Geliştirilmiş Yeni Bir Travers Prototipinin Dinamik Karakterizasyonu

Öz

Bu çalışmada, rijitlik-kütle dağılımını iyileştirmeyi amaçlayan, orta kesitte genişleyen bir profile sahip ve iki adet düşey altıgen boşluk içeren yeni bir demiryolu traversi geometrisi incelenmiştir. Referans B320 tipi travers ile yaklaşık eşit hacim sağlayacak şekilde tasarlanan O-20-230 prototipleri, aynı üç boyutlu yazdırma parametreleri kullanılarak 1:10 ölçekle üretilmiş ve birbirine yakın kütle değerleri elde edilmiştir. Deneysel modal analizlerle frekans yanıt fonksiyonları (FRF) elde edilmiş, modal parametreler Karmaşık Mod Gösterge Fonksiyonu (Complex Mode Indicator Function, CMIF) analizi ile desteklenen En Küçük Kareler Karmaşık Frekans Düzlemi (Least Squares Complex Frequency-domain, LSCF) yöntemi kullanılarak belirlenmiştir. Sonuçlar, O-20-230 geometrisinin temel düşey rezonans frekansını yaklaşık %37 artırdığını, modal sönümleme oranının yaklaşık %43 yükseldiğini ve orta kesitte ölçülen FRF pik genliğinin yaklaşık %45 azaldığını göstermektedir. Global ölçekte CMIF pik değerinin yaklaşık %12 azalması, iyileşmenin özellikle kritik orta kesitte yoğunlaştığını ve yapı genelinde kontrollü bir modal etkinlik azalması sağlandığını ortaya koymaktadır. Elde edilen dinamik sonuçlar mutlak saha performansını temsil eden değerler olarak değil, aynı ölçek ve malzeme koşulları altında topolojik farklılıkların göreli etkisini gösteren karşılaştırmalı göstergeler olarak değerlendirilmelidir. Bulgular, kütle ve hacim büyük ölçüde korunmasına rağmen geometrik tasarım yoluyla optimize edilen rijitlik-kütle dağılımının rezonans frekanslarını baskın uyarım bantlarından uzaklaştırma ve yapısal sönümleme verimliliğini artırma potansiyeline sahip olduğunu göstermektedir.

Anahtar Kelimeler

• Demiryolu traversi
• Modal analiz
• Üç boyutlu yazdırma
• Topoloji optimizasyonu

Dynamic Characterization of a Novel Sleeper Prototype with Improved Stiffness Mass Distribution

Öz

In this study, a novel railway sleeper geometry featuring an expanded mid-section profile and two vertical hexagonal cavities, designed to improve stiffness-mass distribution, was investigated. The O-20-230 prototypes were designed to provide approximately the same volume as the reference B320 sleeper. These prototypes were manufactured at a 1:10 scale using identical three-dimensional printing parameters, resulting in nearly equivalent mass values. Frequency response functions (FRFs) were obtained through experimental modal analysis. Subsequently, modal parameters were identified using the Least Squares Complex Frequency-domain (LSCF) method supported by Complex Mode Indicator Function (CMIF) analysis. The results indicate that the O-20-230 geometry increases the fundamental vertical resonance frequency by approximately 37%, while the modal damping ratio increases by about 43%. Additionally, the FRF peak amplitude measured at the mid-span decreases by approximately 45%. At the global level, the approximately 12% reduction in CMIF peak value indicates that the improvement is mainly concentrated in the critical mid-span region, while a controlled reduction in overall modal activity is achieved across the structure. The obtained dynamic results should not be interpreted as absolute field performance values. Instead, they serve as comparative indicators reflecting the relative influence of topological differences under identical scale and material conditions. The findings further demonstrate that, despite largely preserved mass and volume, an optimized stiffness-mass distribution achieved through geometric design can shift resonance frequencies away from dominant excitation bands and improve structural damping efficiency.

Anahtar Kelimeler

• Railway sleeper
• Experimental modal analysis
• Additive manufacturing
• Topology optimization

Kaynakça

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