Asansör kuyularındaki çelik yapının bilgisayar yardımı ile analizi
Computer aided analysis of elevator hoistway steel structure
Yazar: AHMET BUĞRA ESENLİ
Danışman: YRD. DOÇ. DR. İSMAİL GERDEMELİ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2015
Konu: Makine Mühendisliği = Mechanical Engineering

Özet:
Asansörün genel tanımını; kuyu boşluğunda çelik raylar ile kılavuzlanan ve düşey doğrultuda hareket eden bir kabinin, çelik halatlar veya direkt olarak hidrolik bir piston ile hareket iletiminin sağlandığı, elektro - mekanik taşıyıcı sistem olarak yapmak mümkündür.
Asansörler, tahrik tipine göre; elekrikli ve hidrolik pistonlu olarak ikiye ayrılır. Elektrikli (halatlı) asansörleri ise, makine – motor konumundan dolayı, makine daireli ve makine dairesiz olarak ikiye ayırmak mümkündür. Asansörler, kullanım durumuma göre, yolcu (insan), yük, servis, sedye, araç gibi sınıflara ayrılmaktadır. İstatistiklere göre elektrikli yolcu asansörlerinin kurulum ve kullanım oranı diğer tiplere kıyasla oldukça yüksektir.
Tez ile ilgili yapılan çalışmalarda ilk olarak, asansör kılavuz rayları ve rayları maksimum kuvvet etkisine maruz bırakan fren (paraşüt) tertibatı, bu tertibatı devreye sokan regülatör sistemi araştırılmıştır.
Ardından, 320 kg ve 2000 kg arasında, farklı kapasitelerdeki 21 adet asansörün, raylara etki eden kuvvetleri hesaplanmıştır. Bu hesaplamalar, güvenlik ekipmanı çalışması, normal kullanım - hareket ve normal kullanım - yükleme durumlarına göre yapılmıştır. Etki eden kuvvetlerin, her bir asansör için en büyük değerde olanları kuvvet etkisi olarak esas alınmıştır. Bu kuvvetlerin, NPI, NPU, kare - kutu, HEA ve HEB tiplerinde ve farklı ölçülerdeki 27 adet çelik profile doğrudan iletildiği kabul edilmiş ve kirişlerdeki sehim, eğilme gerilmesi, kayma gerilmesi hesaplanmıştır.
Kuvvet etkisinden dolayı meydana gelen gerilmelerin, çelik çekme dayanımının altında kalmaları şartı ile meydana gelen sehimler arasında karşılaştırma yapılmıştır. Sehim miktarı 0.1 mm'yi geçmeyen ve birim ağırlığı en düşük olan çelik profillerin seçimi yapılmıştır. Sehim miktarı daha az olan veya aynı sehim değeri ile daha büyük birim ağırlığa sahip olan başka bir çelik profilin uygulanması teknik olarak uygun olmasına rağmen, ekonomik açıdan olumsuz bir tercih olmaktadır.
Sonuç olarak 21 adet asansör için çelik profil kiriş seçimi yapılmış ve ileride asansör kapasitelerine göre referans alınmak üzere standartlaştırılması amaçlanmıştır. Seçilen 21 adet çelik profil kirişin gerilme analizi, ANSYS programı ile sonlu elemanlar yöntemi kullanarak yapılmıştır.

Abstract:
In direction of human population rising, both the number of buildings are increasing and the height of buildings are growing vertically. Thus, the construction sector is emerging rapidly. Thanks to rising construction sector and effectuated regulations, the elevator market is growing, also. After all, the number of producer, maintenance and installation companies are increasing. In consideration of this extension, civil engineers, mechanical engineers and electrical engineers of elevator companies which are working with universities and R&D organizations are researching more and more subjects about elevators.
It is possible to define elevator as electro-mechanic transport systems which are running in a vertical shaft, between guide rails and traction by steel ropes or hydraulic pistons. Elevators may be classified according to drive method, as electric elevators, hydraulic elevators and pneumatic elevators. Electric elevators are classified according to traction machine location, as machine room and machine roomless. Additionally, elevators are classified according to usage, as passenger, loads, service, hospital bed, car, etc. According to statistics, electric passenger elevators which have machine rooms are mostly used and installed both Europe and Turkey.
Joints and attachments of guide rails which are the rigid components and provide guiding for the car and the counterweight shall be sufficient to withstand the loads and forces imposed on them in order to ensure a safe operation of the lift. The most important aspect of safe operation of the guide rails is that deflections shall be limited to such an extent, that due to them and operation of the safety devices shall not be affected.
The car shall be provided with a safety gear capable of operating in the downward direction and capable of stopping a car carrying the rated load, at the tripping speed of the overspeed governor, even if the suspension devices break, by gripping the guide rails, and of holding the car there. There are two mostly used safety operation device. Instantaneous safety gear in which the full gripping action on the guide rails is almost immediate. And progressive safety gear in which retardation is effected by a braking action on the guide rails and for which special provisions are made so as to limit the forces on the car, counterweight or balancing weight to a permissible value. In addition to safety gears, overspeed governor which, when the lift attains a predetermined speed, causes the lift to stop, and if necessary causes the safety gear to be applied.
The structure of the well shall conform to National Building Regulations and be able to support at least the loads which may be applied by the machine, by the guide rails at the moment of safety gear operation, in the case of eccentric load in the car, by the action of the buffers, by those which may be applied by the antirebound device, by loading and unloading the car, etc. In addition to that, for the safe operation of the lift the walls shall have a mechanical strength such that when a force of 300 N / 5 cm2 both resist without permanent deformation and resist without elastic deformation greater than 15 mm.
In direction of guide rail regulations and structural requirements of shafts, walls elevator hoistways is mostly built as concrete. But sometimes there is not any concrete wall for fixing guide rails safety. Such as, what if operation with more than one elevator in same shaft, what if using brick wall as a matter of building architectural design, what if dimension of shaft is bigger than usual or car dimension requiry, what if ventilation or pressure shaft be placed in elevator shaft. In these circumstances, some kind of steel section beams are needed to fix guide rails safety.
Rail forces increase in direct proportion to car rated capacity. In addition to rail forces; strain, stress and total deformation of steel beams are up to beam section type, lenght and force point also. In light of these parameters, type of steel section should be choosen correctly. Otherwise some problems may occur, such as safety objections because of weaker steel structural and unnecessary wasted and high cost because of consistent steel structure application.
Ambition of the thesis study, correct steel section chosing, calculation and standardising above case in point within safety using conditions.
Rail loads and forces were calculated according to EN81-1+A3 standard. Such as, running conditions, loading conditions and safety device operation conditions. The rated load is considered to be unevenly distributed over the car area. It is assumed that the safety devices operate simultaneously on the guide rails and that the braking force is equally distributed. It is also assumed that, propped beam which has fixed and roller end is using, according to installation design.
It was specified that 21 numbers of elevator which has different car capacities such as from 320 kg to 2000 kg. Their running and safety operation forces were calculated which affected to guide rails. And maximum normal load is research which is generally occured during brake operation. Founded maximum normal load is assumed that, affect to steel beams directly without any wasting. After all, bending and sharing stresses and deflexions were calculated through 27 number of different steel section types.
During the steel section chosing, it was researched that under 0.1 mm deflexion due to comfortable and safety running operation. Because of more than one result for each elevator, second step of steel section chosing is unit mass of related steel section types. Under related deflexion and the lowest unit mass is researced and specified as suitable for using. Finally, a table was set, that has 21 numbers of elevator and 21 numbers of steel section type and made crosscheck with ANSYS analysis software.
At the end of the thesis study, simple and more useful final table was set according to calculation results. Steel section types may be choosen simply, according to rated capacity of elevator car and approximate beam lenght which is equal to dimension of hoistway depth.