Papers by Emin SUNBULOGLU
Computers in Railways XVI : Railway Engineering Design and Operation, Jul 2, 2018
The Talbot Type Articulation is a classical design for use in articulated freight wagons, where o... more The Talbot Type Articulation is a classical design for use in articulated freight wagons, where one bogie under the coupler serves to both sides coupled. Though being a traditional design, lighter weight wagons designed to transport bulky but lightweight materials return it to one of the alternatives to increase loadto-tare ratio. However, the design criteria of the Couplers are not clearly defined in TSI and recalled standards, but simply recalled to be stronger than other coupling means at ends. This fact requires other challenges of loading case reviews, since the coupling is acting both in tensile and compressive loads, and it is the means of generating the intermediate joint. To end up with a design, a way of generating the possible load cases and combining these into the scope of the DVS fatigue code for fatigue assessment is presented in this study, along with experimental verification of the model.
Journal of Sound and Vibration, 2003
ABSTRACT An exact analytical method is presented for predicting the undamped natural frequencies ... more ABSTRACT An exact analytical method is presented for predicting the undamped natural frequencies of beams with thin-walled open cross-sections having no axis of symmetry. The governing differential equations give a characteristic equation of the 12th order with real coefficients. The roots are found numerically and the exact boundary conditions are considered especially for free ends to obtain natural frequencies. The simpler cases of neglecting cross-sectional warping and/or rotary inertia are also dealt with. It is seen that when the effect of rotary inertia is neglected significant errors incur for some boundary conditions, cross-section thicknesses and mode numbers. This is more profound when the warping effect is taken into account.
Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association, Jan 9, 2016
Various types of shortening osteotomies and prosthesis are used for femoral reconstruction in tot... more Various types of shortening osteotomies and prosthesis are used for femoral reconstruction in total hip arthroplasty of the high hip dislocation. This biomechanical study investigates whether step-cut osteotomies result in better stability than oblique osteotomies and cylindrical femoral stems enhance stability of the osteotomy more than conical stems, and which osteotomy and prosthesis type maintain the stability better after cyclical loading. Oblique and step-cut shortening osteotomies were compared under axial and rotational forces, using synthetic femur models and conical or cylindrical femoral prostheses. The models underwent cyclic loading for 10,000 cycles at 3 Hz (100-1000 N axial bending or 0.5-10 Nm torque). After the completion of cyclic loading, the models were loaded until failure. Stiffness values before and after cyclical loading, and failure loads were the outcome parameters. Relative displacements at the osteotomy sites were also measured using 3-Dimensions Digital ...
Acta Orthopaedica Et Traumatologica Turcica, Feb 1, 2005
Objectives: This study was designed to compare the biomechanical characteristics of non-anatomic ... more Objectives: This study was designed to compare the biomechanical characteristics of non-anatomic (far from joint) and anatomic (close to joint) levels of tibial tunnel fixation with soft tissue graft using a soft tissue interference screw in anterior cruciate ligament (ACL) reconstruction.
Acta Neurochir, 2004
Background. Anterolateral oblique corpectomy is an alternative approach to treatment of multileve... more Background. Anterolateral oblique corpectomy is an alternative approach to treatment of multilevel cervical spinal disease. It is stated that the approach does not cause instability in the patients with hard discs, so fusion or instrumentation is not required. The authors undertook a study on stability of the cervical spine by an animal model to establish if this approach causes instability.
Ulusal Travma Ve Acil Cerrahi Dergisi Turkish Journal of Trauma Emergency Surgery Tjtes, Aug 1, 2005
Sakrum kırıkları direkt ve indirekt travmalardan sonra görülmektedir. Direkt travmalar, sakral bö... more Sakrum kırıkları direkt ve indirekt travmalardan sonra görülmektedir. Direkt travmalar, sakral bölgenin künt travmaları veya ateşli silah yaralanmaları şeklinde olup nadiren görülürler. Daha sık görülen indirekt travmalar ise motorlu araç kazaları ve belirli yükseklikten düşme sonrasında kemiğin dik ekseninde olan kayma hasarı sonrasında oluşurlar.
The Journal of Foot and Ankle Surgery, 2015
Proximal metatarsal osteotomy is the most effective technique for correcting hallux valgus deform... more Proximal metatarsal osteotomy is the most effective technique for correcting hallux valgus deformities, especially in metatarsus primus varus. However, these surgeries are technically demanding and prone to complications, such as nonunion, implant failure, and unexpected extension of the osteotomy to the tarsometatarsal joint. In a preclinical study, we evaluated the biomechanical properties of the fixator and compared it with compression screws for treating hallux valgus with a proximal metatarsal osteotomy. Of 18 metatarsal composite bone models proximally osteotomized, 9 were fixed with a headless compression screw and 9 with the mini-external fixator. A dorsal angulation of 10° and displacement of 10 mm were defined as the failure threshold values. Construct stiffness and the amount of interfragmentary angulation were calculated at various load cycles. All screw models failed before completing 1000 load cycles. In the fixator group, only 2 of 9 models (22.2%) failed before 1000 cycles, both between the 600th and 700th load cycles. The stability of fixation differed significantly between the groups (p < .001). The stability provided by the mini-external fixator was superior to that of compression screw fixation. Additional testing of the fixator is indicated.
Acta orthopaedica et traumatologica turcica, 2005
We investigated the biomechanical characteristics of anterior or posterior tibial tunnel placemen... more We investigated the biomechanical characteristics of anterior or posterior tibial tunnel placement of the soft tissue graft with a soft tissue interference screw in anterior cruciate ligament (ACL) reconstruction. Twelve bovine tibiae and digital extensor tendons were divided into two homogeneously equal groups after they were stripped of all soft tissues. Tibial tunnels were prepared and digital extensor tendons were fixed at nonanatomic (apart from the joint) anterior (n=6, group I) or posterior (n=6, group II) tibial tunnel positions with a soft tissue metal interference screw, 9x30 mm in size. All the specimens were cycled 500 times from 50 to 250 N at 1 Hz frequency in a servo hydraulic test device, after which ultimate load-at-failure testing was performed at a rate of 20 mm/min. The mean screw insertion torque values were 8.2+/-2.4 Nm and 8.4+/-2.8 Nm in groups I and II, respectively (p=0.88). No significant differences were found between the two groups with respect to graft ...
Journal of Plastic Surgery and Hand Surgery, 2014
Abstract Abdominal wall hernias are often diagnosed on clinical examination or encountered intrao... more Abstract Abdominal wall hernias are often diagnosed on clinical examination or encountered intraoperatively during an abdominoplasty. The aim of this study is to evaluate the long-term results of the use of dermal automesh for the repair of incidental hernias during abdominoplasty operations, and to perform a comparative analysis of the biomechanical strengths of dermal automesh vs biological tissue graft. Between 2008-2012, dermal automesh was used in 12 patients for hernia repair. After repair of hernia, dermal automesh was applied over the repaired area in an onlay fashion. Postoperative follow-up was performed by physical examination and magnetic resonance imaging (MRI) of the abdominal wall. Biomechanical test was performed with prepared samples from excised abdominal panniculus for tensile strength and yield power. Mean age was 45 years (range = 36-54 years). Total follow-up was 26 (14-52) months. MRI studies showed that there were no hernias or defects of the anterior abdominal wall. The tensile strength of the dermal mesh was measured as 15.9 ± 6.0 Mpa (6.4-24.5), maximum load before yield measured 680 ± 175.2 N (336.0-856.0). In conclusion, dermal automesh is a useful option for surgeons who encounter undiagnosed hernias during abdominoplasties.
International Journal of Crashworthiness, 2013
ABSTRACT Rollover of railroad passenger cars is one of the most serious accidents having high rat... more ABSTRACT Rollover of railroad passenger cars is one of the most serious accidents having high rates of injuries and fatalities. Therefore, the railroad passenger car structures should satisfy the rollover crashworthiness requirements in order to protect the occupants. In this paper, rollover crashworthiness of a railroad passenger car called N13-type' used by Turkish State Railways is investigated. To assess the rollover crashworthiness, rollover simulations of the full scale and detailed passenger car models onto a rigid ground are completed by using a non-linear explicit finite element code, Abaqus. The numerical model is validated with static and modal experimental measurements before running rollover analyses of the railroad passenger car. Good agreement is observed between tests and finite element results, which indicate that the numerical model accurately represents the real structure. Simulations are performed in accordance with the regulation of ECE R66. Based on this standard, two different rollover scenarios are considered. In the first scenario, lateral rollover simulation is performed at the standard angular velocity due to ECE R66 regulation. The second scenario is performed at the double of this angular velocity to investigate the crashworthiness behaviour under exaggerated conditions. As a result of the analyses, it is observed that the residual space remains undamaged during and after the rollover, and passenger car is able to pass the required regulations.
Neurology India, 2009
This experimental biomechanical study was performed to determine the effects of multilevel anteri... more This experimental biomechanical study was performed to determine the effects of multilevel anterior cervical discectomy and excision of posterior longitudinal ligament (PLL) to stabilize the cervical spine using an in vitro animal model. Fifty fresh cadaveric C3-C6 sheep spine specimens were divided into five experimental groups: Group A was the control group; Group B, one-level discectomy; Group C, two- level discectomy, Group D, three-level discectomy, and Group E, three-level discectomy and excision of PLL, respectively. The specimens were subjected to non-destructive loads cycled from zero to five Newton-meter for flexion, extension, right and left lateral bending, and axial rotation on an electrohydraulic test machine. Load displacement curves were obtained via collected data using strain gauges. The values were obtained for all five groups, statistical differences were determined respectively (P<0.05, ANOVA). One-level discectomy was less stable than the control group, two-level discectomy was less stable than one-level discectomy and three-level discectomy was less stable than two-level discectomy, respectively (P<0.05). Excision of PLL did not seem to affect stability (P>0.05). Our data suggested that cervical discectomy decreases stability of sheep spine pieces.
Knee Surgery, Sports Traumatology, Arthroscopy, 2011
Tensile and knot properties of new generation (polyblend) and traditional suture materials in ort... more Tensile and knot properties of new generation (polyblend) and traditional suture materials in orthopedic surgery were investigated in standard laboratory conditions. Study focused on Fiberwire No. 5 and 2, Ethibond No. 5, 2 and 00, Orthocord No. 2, MaxBraid No. 2, Prolene No. 0 and 00, PDS No. 0 and 00, and Vicryl No. 2, 0 and 00. A 27-cm suture loop was fastened with 10 knots for ten samples for each type. Test parameters were tensile load to failure, elongation at failure point and knot slippage, and volume of 10-fold knots. Results were compared using ANOVA test. Failure load of No. 5 Fiberwire (625.0 ± 30.0 N) was significantly higher compared to all other suture types. Tensile strengths of MaxBraid No. 2 (287 ± 11 N) was significantly stronger compared to two other No. 2 polyblend sutures types and Ethibond No. 5. Knot slippage of Fiberwire No. 5 (14 ± 1.9 mm) was significantly higher compared to all other suture types. Ethibond No. 2 (0.1 ± 0.3 mm) had the lowest knot slippage. Elongation at the failure point of Fiberwire No. 2 (5%) was significantly lower than all other suture types. Mean calculated knot volume of #5 Fiberwire (73 ± 6.9 mm(3)) was significantly higher compared to #5 Ethibond (53 ± 4.8 mm(3)). Results of the study proved presence of significant differences between tensile and knot properties of various suture types and sizes. Loop security of larger diameter sutures is not always higher than thinner sutures. Suture elongation and knot slippage are important failure modes for high-diameter sutures and short-suture loops.
Journal of Oral Rehabilitation, 2010
Achievement of primary stability during surgical placement of dental implants is one of the most ... more Achievement of primary stability during surgical placement of dental implants is one of the most important factors for successful osseointegration depending on various anatomical, surgical and implant-related factors. Resonance frequency analysis (RFA) has been shown as a non-invasive and objective technique for measuring the stability of implants. The aim of this study was to evaluate the effect of some surgical and implant-related factors in enhancing primary stability and to estimate a correlation between RFA and insertion torque (IT) in proximal regions of cow ribs representing cancellous bone. Fifteen implant beds were prepared in the most proximal region of six fresh cow ribs. Ninety implants with three different shapes and two different diameters were placed with two different surgical techniques, and the primary stability was compared using RFA and IT. Significantly higher RFA and IT values were achieved when under-dimensioned drilling was used as the surgical method (P < 0AE01); significantly higher IT values were obtained with the use of wider implants (P < 0AE01) and partially conical Astra Tech implants showed the highest IT values (P < 0AE01). When all the implants were considered, significant correlations between the IT and RFA values were noted (%40AE6, P < 0AE05). Partially conical implants with a wide diameter to be placed with the modified surgical technique proposed appear to be useful in enhancing the primary stability in cancellous bone.
Journal of Bone and Joint Surgery - British Volume, 2008
We compared time-dependent changes in the biomechanical properties of single-and double-row repai... more We compared time-dependent changes in the biomechanical properties of single-and double-row repair of a simulated acute tear of the rotator cuff in rabbits to determine the effect of the fixation techniques on the healing process. A tear of the supraspinatus tendon was created in 80 rabbits which were separated into two equal groups. A single-row repair with two suture anchors was conducted in group 1 and a double-row repair with four suture anchors in group 2. A total of ten intact contralateral shoulder joints was used as a control group. Biomechanical testing was performed immediately post-operatively and at four and eight weeks, and histological analysis at four and eight weeks. The mean load to failure in group 2 animals was greater than in group 1, but both groups remained lower than the control group at all intervals. Histological analysis showed similar healing properties at four and eight weeks in both groups, but a significantly larger number of healed tendon-bone interfaces were identified in group 2 than in group 1 at eight weeks (p &lt; 0.012). The ultimate load to failure increased with the number of suture anchors used immediately post-operatively, and at four and eight weeks. The increased load to failure at eight weeks seemed to be related to the increase in the surface area of healed tendon-to-bone in the double-row repair group.
Computers & Structures, 2006
The new Galata Bridge, which is one of the largest bascule type bridges in the world, was built d... more The new Galata Bridge, which is one of the largest bascule type bridges in the world, was built during the period of 1985-1993 to link both sides of the Golden Horn in Istanbul, replacing old pantoon-type bridge built in 1912 at the same location. Soon after it has been taken into service, some very serious cracks and deformations were noticed on the flaps of bridge in 1998. In this study, the results of experimental stress and vibration studies on one of the flaps are given after the damages are repaired. Moreover, the first natural frequency, higher resonance frequencies and corresponding mode shapes have been obtained by using finite element method and results compared with experiment measurements. These studies unveiled that the first natural frequency of the flap structure is in the range of the hydraulic oil circuit natural frequency that causes resonancy during the expanding operation of flaps, especially when flap opening angle is within a certain range. As the second stage of the study, some design variations are applied to flap structure model and frequency responses are obtained for different design trials. Consequently, some design rules are proposed that should be considered during the design stage of bascule type bridges. On the other hand, results show that several natural frequencies of flaps, particularly during the opening period, are within the earthquake frequency ranges. This fact has been proposed as another important problem especially for this bridge as Istanbul is located near a major earthquake fault.
timak.balikesir.edu.tr
Bu çalışmada, bir yolcu treni vagonunun rijit bir duvara çarpması sonlu elemanlar yöntemi kullanı... more Bu çalışmada, bir yolcu treni vagonunun rijit bir duvara çarpması sonlu elemanlar yöntemi kullanılarak benzetilmiştir. Modeli doğrulamak amacıyla, vagonun çarpışma analizlerine başlamadan önce değişik tiplerdeki statik yükleme durumları için elde edilen deneysel test sonuçları ile ...
Advances in Therapy, 2007
Perforation of the tympanic membrane occurs frequently as a result of infection, external trauma,... more Perforation of the tympanic membrane occurs frequently as a result of infection, external trauma, and high-level impulsive sound pressure, such as that associated with an explosion. Many different surgical techniques can be used to repair the tympanic membrane and ossicles. Clinical operations such as tympanoplasty are undertaken to repair the damaged tympanic membrane and ossicles, thus improving hearing and reducing the chance of infection. The membrane is repaired or replaced with the use of graft materials, either from the patient's body or from artificial sources. The selection of graft material is very important because, as much as possible, it must exhibit the same dynamic behavior as the natural membrane. To compare various allograft materials, investigators developed a model of the ear on which different graft materials can be replaced. Three different membrane materials-irradiated allograft dura (Tutoplast ® Dura; IOP Inc., Costa Mesa, Calif), irradiated allograft fascia lata (Tutoplast Fascia Lata; IOP Inc.), and irradiated allograft fascia temporalis (Tutoplast Fascia Temporalis; IOP Inc.)-were used. Vibration responses of these membrane materials produced by defined sound signals with different frequencies were recorded by a small strain gauge; the spectra of sound for various corresponding input signals were recorded, and the results were compared with those of the sample graft material. Tutoplast Fascia Lata accomplished the best dynamic performance in vitro. Additional clinical and experimental data are needed, however, to determine which of these materials provides the best audiological and clinical performance.
acta orthopaedica et traumatologica turcica, 2008
Amaç: Plikasyon uygulanan eklem kapsülünde ameliyat sonrası erken dönemde meydana gelen biyomekan... more Amaç: Plikasyon uygulanan eklem kapsülünde ameliyat sonrası erken dönemde meydana gelen biyomekanik değişimler araştırıldı ve debridman ile kapsül iç yüzünde kanamalı bir yüzey oluşturulmasının iyileşme üzerine etkisi değerlendirildi. Çalışma planı: Elli dört yetişkin Yeni Zelanda beyaz tavşanının 48'inin tek taraf diz medial eklem kapsülüne tek başına (n=24) ya da debridmanla kapsül iç yüzünde kanamalı bir yüzey oluşturulduktan sonra (n=24) plikasyon yapıldı. Altı tavşanın sağlam dizi kontrol grubunu oluşturdu. Ameliyat sonrasında tavşanların dizleri tespit edildi. Debridman uygulanan ve uygulanmayan gruplarda altışar tavşanın yaşamı sırasıyla ameliyattan hemen sonra, birinci ikinci ve üçüncü haftalarda sonlandırıldı. Her altgrupta beş tavşan mekanik testler için, bir tavşan ise histolojik değerlendirme için kullanıldı. Sonuçlar: Deney gruplarında kopma kuvveti üçüncü haftaya kadar kontrol grubundan yüksek bulundu (p<0.01). Bu fark üçüncü haftada ortadan kalktı (p>0.05). Ayrıca, birinci haftadaki kopma kuvveti, ikinci ve üçüncü hafta sonuçlarından anlamlı derecede yüksekti (p<0.01). İkinci ve üçüncü hafta arasında anlamlı fark saptanmadı (p>0.05). Debridman uygulanmayan gruba göre, debridman uygulanan grubun birinci haftadaki kopma kuvveti belirgin olarak daha azdı (p<0.01). Bu fark ikinci ve üçüncü haftalarda gözlenmedi (p>0.05). Histolojik örneklerde deney gruplarında tüm haftalarda benzer bulgular elde edildi; birinci haftadan itibaren her iki grupta da artan fibrozisle birlikte iyileşme gözlendi. Çıkarımlar: Plikasyondan sonra kapsül, sağlam kapsülden daha zayıf değildir. Debridmanla daha hızlı veya daha iyi iyileşme olduğu gösterilememiştir. Debridman kapsülün biyomekanik özelliklerini olumsuz etkileyebilir.
Acta Neurochirurgica, 2004
Background. Anterolateral oblique corpectomy is an alternative approach to treatment of multileve... more Background. Anterolateral oblique corpectomy is an alternative approach to treatment of multilevel cervical spinal disease. It is stated that the approach does not cause instability in the patients with hard discs, so fusion or instrumentation is not required. The authors undertook a study on stability of the cervical spine by an animal model to establish if this approach causes instability.
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Papers by Emin SUNBULOGLU