Publication: Havacılık sektöründe yedek parça envanter problemlerine simülasyon ve çok kriterli karar verme yöntemleri ile hibrit bir çözüm yaklaşımı
Abstract
Havacılık bakım/ onarım sektöründe faaliyet gösteren işletmeler için, yedek parça envanterinin yönetimi ve atölye iş akış sürecinin iyileştirilmesi son derece önemli hedeflerdir. Bu hedeflerin gerçekleştirilebilmesi için uygulama safhasında, Yöneylem Araştırması tekniklerinden olan Çok Kriterli Karar Verme ve Simülasyon entegre olarak kullanılmıştır. Uçaklara ait yedek parça envanter problemlerine çözüm getirmek için, atölyeye uçaklardan sökülüp tamir görmek için gelen komponentlerin tamir önceliklerinin belirlenmesi ve tamir bakım hattının iyileştirilmesi gerekmektedir. Bu sebeplerden ötürü çalışmada, havacılık bakım onarım sektöründe yedek parça problemlerine ilişkin karşılaşılan bekleme hattı problemlerinin çözümünde Simülasyon ile bütünleşik ÇKKV yaklaşımı kullanılmıştır. Uygulama ile atölyede tamir sırası bekleyen komponentlerin öncelik sıralarının belirlenmesi ve komponentlerin kuyruk bekleme süresini azaltan, komponent verimliliğini ve kaynak kullanım oranlarını arttıran, âtıl kapasite kullanımını ortadan kaldıran senaryoların geliştirilmesi ve kaynak sayılarında değişiklikler yapılarak farklı senaryo çıktılarının elde edilmesi amaçlanmıştır. Çalışmada uçak komponentlerinin atölyeye gönderildikten sonra hangi sırada tamir göreceğinin belirlenmesi için ÇKKV teknikleri ile simülasyon bütünleşik olarak gerçekleştirilmiş ve uygulamada tamir görmek için bekleyen komponentlerin oluşturmuş olduğu bekleme hattı problemi de incelenmiştir. Bu çalışmada; atölyeye uçaklardan sökülerek arızalı olarak gelen ve kuyrukta bekleyeniiyedek parçaların tamir önceliklerini belirlemek ve atölyenin iş akış sürecinin ve performans değerlendirme ölçütlerinin simülasyon ile incelenmesi amaçlanmıştır.Uygulamada; ÇKKV, Kuyruk Teorisi ve Simülasyon yöntemleri kullanılmıştır. Uygulamada komponentlerin önceliklendirilmesi aşamasında VIKOR yöntemi kullanılmış ve komponentlerin tamir bakım öncelikleri belirlenmiştir. VIKOR’dan elde edilen öncelik sırasına göre simülasyon ile atölye sistemine ait model simüle edilmiş ve senaryoların ortaya konulmasında ARENA kullanılmıştır. ARENA ile atölye iş akış sürecine ait olan model simüle edilerek, sistemin davranışları değişen koşullar altında incelenmiş ve çıktılar elde edilmiştir. Çalışmanın son kısmında simülasyon ile ortaya konulan senaryoların öncelik sıraları PROMETHEE yöntemi ile ve kriterlerin ağırlıkları ise ENTROPİ yöntemiyle elde edilmiştir. Yapılan senaryo sıralaması sonucunda atölye için en uygun senaryo belirlenmiş ve elde edilen bulgular yorumlanarak şirkete çeşitli öneri ve tavsiyeler sunulmuştur.
For companies carrying on businesses in aviation maintenance/ repairment industry, management of spare part inventories and improvement of factory workflow process are very crucial goals. Multiple criteria based decision-making and simulation, as a couple of techniques of operational research are used integratedly for making these goals achieved in the implementation phase. For finding a solution for inventory problems of spare parts for aircrafts, it is essential to determine the priorities of the components, which are detached and taken to the factories, as well as the improvement of service lines. For these reasons, in this study, multiple criteria based decision-making approach with simulation was used for a solution to problems related to spare part troubles faced in aviation maintenance and repairment industry. With the implementation, it was aimed at determining priorities of the components waiting to be repaired, developing scenarios about increasing component productivity, utilization rates of sources and reducing the waiting-period on lines and elimination of the usage of unproductive capacity as well. Also, the outputs of different scenariosacquired by changing source quantities are aimed. In this study, to determine the priority order of the aircraft components for repairment, multipleivcriteria based decision-making techniques and simulation were applied and the holding track problem caused by the components waiting for maintenance was examined as well. In my thesis, my goal is to determine the maintenance priorities of the broken spare parts detached from aircrafts and waiting in holding tracks and to improve the process of factory’s workflow with simulation. In the implementation, methods of multiple criteria-based decision-making, Queuing theory and simulation were wielded. Conducts of the system under the various circumstances were examined by simulating the model which belongs to process of factory workflow. And, their outputs were collected. In the implementation, VIKOR method was used in the phase of prioritization of the components and maintenance/ repairment priorities of the components were determined. In accordance with the order of priority of VIKOR, model concerning to factory system was simulated with simulation and ARENA program was providing scenarios. In the last part of the study, the orders of precedence of the scenarios produced with simulation were obtained with PROMETHEE method. Also, the parameters of the criteria were obtained with ENTROPY method. As a result of the order of precedence, the most suitable scenario for the factory has been specified and various advices were presented to the company after the interpretation of acquired findings.
For companies carrying on businesses in aviation maintenance/ repairment industry, management of spare part inventories and improvement of factory workflow process are very crucial goals. Multiple criteria based decision-making and simulation, as a couple of techniques of operational research are used integratedly for making these goals achieved in the implementation phase. For finding a solution for inventory problems of spare parts for aircrafts, it is essential to determine the priorities of the components, which are detached and taken to the factories, as well as the improvement of service lines. For these reasons, in this study, multiple criteria based decision-making approach with simulation was used for a solution to problems related to spare part troubles faced in aviation maintenance and repairment industry. With the implementation, it was aimed at determining priorities of the components waiting to be repaired, developing scenarios about increasing component productivity, utilization rates of sources and reducing the waiting-period on lines and elimination of the usage of unproductive capacity as well. Also, the outputs of different scenariosacquired by changing source quantities are aimed. In this study, to determine the priority order of the aircraft components for repairment, multipleivcriteria based decision-making techniques and simulation were applied and the holding track problem caused by the components waiting for maintenance was examined as well. In my thesis, my goal is to determine the maintenance priorities of the broken spare parts detached from aircrafts and waiting in holding tracks and to improve the process of factory’s workflow with simulation. In the implementation, methods of multiple criteria-based decision-making, Queuing theory and simulation were wielded. Conducts of the system under the various circumstances were examined by simulating the model which belongs to process of factory workflow. And, their outputs were collected. In the implementation, VIKOR method was used in the phase of prioritization of the components and maintenance/ repairment priorities of the components were determined. In accordance with the order of priority of VIKOR, model concerning to factory system was simulated with simulation and ARENA program was providing scenarios. In the last part of the study, the orders of precedence of the scenarios produced with simulation were obtained with PROMETHEE method. Also, the parameters of the criteria were obtained with ENTROPY method. As a result of the order of precedence, the most suitable scenario for the factory has been specified and various advices were presented to the company after the interpretation of acquired findings.