Browsing by Author "Mansouri, Deniz"

Now showing 1 - 4 of 4

Metadata only
The effect of spotwelds and structural adhesives on static and dynamic characteristics of vehicle body design
(Sage, 2021-10) Tuncer, Gözde; Mansouri, Deniz; Şendur, Polat; Mechanical Engineering; ŞENDUR, Polat; Tuncer, Gözde; Mansouri, Deniz
Spotwelding and structural adhesive applications are two important processes in the automotive industry as they are closely associated with the functional requirements, weight, and cost of the vehicle. Even though there is a vast body of literature on their mathematical models, the effect of these processes on key vehicle performance indices and optimization is rather limited. Besides, the weight benefit of these processes in terms of functional requirements has not been investigated. There are multiple objectives of the paper to fill this gap: (i) to quantify the effect of structural adhesives on the key performance indices (KPIs) of a vehicle body, (ii) to rank the components based on their gauge sensitivities for body KPIs using topometry optimization, (iii) to assess the weight impact of the structural adhesive applications using the gauge sensitivity results, (iv) to determine the optimum layout of the structural adhesive applications using topology optimization, (v) to present a methodology for automotive original equipment manufacturers (OEMs) to determine the “critical welds” on the vehicle body and reduce the number of spotwelds as a potential cost reduction action. For this purpose, a validated finite element model of 2010 Toyota Yaris has been used. Optimization of the structural adhesives and spotwelds was carried-out using SIMP (Solid Isotropic Material with Penalization) based topology optimization. The thickness of each panel is ranked using topometry optimization results. Automotive OEMs can use the proposed methodology to optimize the structural adhesives or spotwelding processes in their product development cycle.
Metadata only
Fatigue characteristics of continuous welded rails and the effect of residual stress on fatigue-ratchetting interaction
(Taylor & Francis, 2020-03-16) Mansouri, Deniz; Şendur, Polat; Yapıcı, Güney Güven; Mechanical Engineering; ŞENDUR, Polat; YAPICI, Güney Güven; Mansouri, Deniz
The importance of ratchetting-fatigue interaction is garnering interest due to complex failure mechanism of rail welds under cyclic loading. The objective of this paper is to investigate the fatigue characteristics of continuous welded rails (CWRs) and the effect of residual stress on fatigue-ratchetting interaction. For this purpose, UIC60 rails have been modeled using a three-dimensional finite element model, including a combination of nonlinear kinematic and isotropic hardening. In addition, the interaction between cyclic loading and the effect of residual stress on fatigue is taken into consideration. Finite element model is validated against representative experimental findings. Smith-Watson-Topper (SWT) method is utilized in order to estimate the fatigue life of rail welds under static and cyclic loading. Lower fatigue life is predicted with increasing load due to the contact between rails and wheels. Simulation results also show that failure in the form of ratchetting occurs during the 10,236th cycle, while failure corresponds to the 15,290th cycle and the 145,161st cycle based on the SWT and Coffin-Manson fatigue models, respectively. These findings suggest that investigations on ratchetting and fatigue should be carried out simultaneously to estimate the failure of the CWRs.
Metadata only
A novel driving pattern to actualize haptic effects in mobile devices
(IEEE, 2021-05) Kirişken, Barbaros; Mansouri, Deniz; Şendur, Polat; Özkan, Bebek; Mechanical Engineering; ŞENDUR, Polat; BEBEK, Özkan; Kirişken, Barbaros; Mansouri, Deniz
Haptic interactions in consumer devices have become more critical with immersive streaming content by including high-resolution video and sound as well as tactile information. Mobile devices such as tablets and smartphones are significantly limited for creating effective haptic illusions as they are too small in size to accommodate complex actuators and are without mechanical support. Recent studies and commercial products show that the use of larger and complex multi-coil linear resonant actuators (LRAs) can significantly improve tactile perception quality at the expense of significant design constraints such as size and cost. In this study, a novel driving pattern and complete system design are presented that enables similar quality haptic effects using a simple LRA system. The proposed driving pattern consists of segmented signals with different frequencies and duty cycles determined from finite element-based modal analysis, and it was used to simulate the two most common touch controls, the button and slider, on a mobile device. Numerical and experimental results showed that the system can achieve a 3x reduction in cost, a 9 x reduction in weight, and a 6 x reduction in volume. User tests comparing smartphones with the novel LRA driving pattern and the benchmark devices demonstrated the feasibility of a low-cost solution to improve haptic effects and illusions.
Metadata only
Topology optimization of constrained and unconstrained damping layers
(Canadian Acoustical Association, 2019) Mansouri, Deniz; Şendur, Polat; Mechanical Engineering; ŞENDUR, Polat; Mansouri, Deniz
Damping is an effective way of suppressing mechanical vibrations. Passive constrained and unconstrained layer damping patches are often used in the industry as damping solution for vibrations and acoustics problems. In this study, topology optimization methods were applied to the finite element models (FEM) of plates and damping patches in order to determine the critical locations for the frequency range of interest. For that purpose, MSC. Nastran SOL 200 optimization is used for both topology and thickness optimization. The structures are excited at single point and the acceleration of the plate at a pre-determined location is considered as output. The objective of the optimization is chosen as the minimization of the acceleration spectrum up to 500 Hz. The optimized damping patch topology is compared to the base plate with full application of damping patch on frequency response functions. The simulation results from topology and thickness optimization show that these methods can effectively improve the frequency response functions.