بررسی رفتار ارتعاشی دال خط ریل مدفون به روش عددی

نوع مقاله : علمی - پژوهشی

چکیده

هدف از ارایه مقاله حاضر بررسی رفتار ارتعاشی سیستم ریل مدفون در اثر اعمال بار هارمونیک است. رفتار ارتعاشی این سیستم به طورعمده تابع الاستیسیته مصالح دورگیر ریل و هندسه شیار جاگذاری آن است. بررسی مطالعات انجام شده در زمینه این سیستم نشان می‌دهد که تاکنون تأثیر این پارامترها بر ارتعاشات منتشره محیطی مشخص نشده است . به این منظور در مطالعه حاضر مدل عددی اجزاء محدود دال خط ریل مدفون با استفاده از نرم افزار اجزاء محدود ABAQUS توسعه داده شده و نتایج آن در حالت استاتیکی با مدل ارایه شده توسط  ایسولد و همکاران  مقایسه و به این ترتیب مدل معتبر سازی شده است. سپس با توسعه مدل معتبرسازی شده  در شرایط دینامیکی، بر روی پارامترهای هندسی شیار نشیمن ریل و مصالح  الاستیک  دورگیر آن به همراه دامنه بار هارمونیک و فرکانس آن،  تحلیل حساسیت صورت گرفته و ارتعاشات محیطی بررسی شده است. نتایج  تحلیلها نشان می دهد که مقدار مدول الاستیسیته ترکیب دورگیر، تأثیر بسزایی در میزان ارتعاشات داشته و با افزایش  آن از 1 به 10 مگاپاسکال، به میزان این ارتعاشات به شدت افزوده شده است . همچنین با بررسی اثر هندسه شیار نشیمن ریل ملاحظه می شود که افزایش مساحت آن منجر به کاهش ارتعاشات منتشره در محیط اطراف می‌گردد. از سوی دیگر زمانی که دامنه  بار هارمونیک اعمالی از 5/1 تن به 9 تن افزایش یابد، دسی بل ارتعاشات  محیطی بیشتر شده و با افزایش فرکانس آن، مقدار این ارتعاشات کاهش می یابد. بررسی نتایج  ارتعاشی نشان می دهد که این پدیده، در فرکانس 5 هرتز، بیشترین و در فرکانس 50 هرتز کمترین مقادیر را به خود اختصاص داده است. در مجموع میزان ارتعاشات دال خط مذکور در فرکانس بار اعمالی بیشتر از 60 هرتز قابل توجه ناست.

کلیدواژه‌ها


عنوان مقاله [English]

Investigating the Vibrational Behavior of Embedded Rail Slab Track Using Numerical Method

چکیده [English]

The vibrational behavior of embedded rail system is mainly a function of the elasticity of rail embedding resin as well as the geometry of rail seating trough. Reviewing the technical literature in the field of embedded rail slab tracks (ERST) system reveals any study on investigating of the effect of these parameters on the environmental vibration caused by ERST. In the present study by developing a 2D finite element model of embedded rail slab track using ABAQUS software the mentioned issue has been investigated. In this matter and as first stage, the results of the developed model under static loads has been compared with those reported by Esveld et all ( ) and consequently a verified model has been established. In continue, by using the validated model, the vibrational behavior of the model especially the case of environmental vibrations has been studied. In this regard an extensive parametric study has been fulfilled on four key parameters as load amplitude, load frequency, embedding resin elasticity and the dimensions of rail seating trough. The results of these analyses indicated that the varying the elasticity module of embedding resin in the range of 1 to 10 MPa had a great effect on the environmental vibrations. On the other hand it has observed that increasing the trough geometry and consequently its area section leads to reducing environmental vibrations. From another point of view, when the amplitude of the applied harmonic load increases from 1.5 to 9 tons, the intensity of environmental vibrations increases while by increasing the load frequency, this parameter show decrease. Focusing on loading frequency proved that the maximum and minimum vibrations are corresponding to 5 Hz and 50 Hz and the vibrational effects no so important for frequencies more than 60 Hz.

کلیدواژه‌ها [English]

  • Embedded rail slab track
  • Environmental Vibrations
  • Elasticity module of embedding rail resin
  • trough geometry
  • Finite element method
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