One of the main focuses in transportation engineering is the application of sandwich materials in order to create safer and efficient vehicles. The main focus of this study was the application of 3D computed tomography for analyzing the responses of sandwich panels with micro lattice core subjected to impact loading. Micro lattice specimens were manufactured using Ti-6Al-4V powder by means of a direct metal laser sintering system. A theoretical model was applied for predicting the failure initiation loads under impact loading. The predictions presented good consistency with the experimental measurements. The 3D computed tomography system was used for the analysis of the collapse modes of the micro lattice sandwich panels after low-velocity impact tests. Experimental and theoretical results proved that lightweight sandwich panels with micro lattice cores are excellent energy absorbers and, therefore, they could have significant applications in the transportation industry.

The aim of this scientific work was the analysis of the micro lattice structures under uniaxial quasi-static compression loading with regard to the effect of unit cell size and strut diameter. A wide range of cubic lattice blocks designed in a CAD software were fabricated using Ti6Al4V (Ti64) metal powder and two different production parameters in the direct metal laser sintering machine. The failure modes of the specimens were investigated and the 3D Computed Tomography system was used for the morphological analysis of the struts. An analytical model, developed by Gibson and Ashby, was adapted to the titanium body centered cubic lattices in order to predict their mechanical properties for compressive loading. Moreover, the compressive responses of the lattice structures were also studied using a numerical approach based on finite element analysis. Both experimental and theoretical results presented good agreement in terms of mechanical properties of the body centered cubic lattices and showed that such structures are great energy absorbers. Theoretical approaches gave significant results on the predictions of mechanical properties of these cellular structures, which are suitable for biomedical and transport engineering applications, in order to save manufacturing cost and time.

The main advantage of using sandwich structures is their high strength, high energy absorbing capacity and high bending stiffness to weight ratio. Therefore, they are unique for the applications where the light-weight design philosophy is a crucial aspect. While sandwich structures with polymeric foams have been applied for many years, recently there is a growing interest on a new generation composite sandwiches with metallic foam core. In this study, the influence of pores per inch (ppi) of the foam on low-velocity impact response of the entire panel has been investigated. The glass fibre reinforced plastic (GFRP) skins produced by vacuum bagging technique in the study were easily bonded to the foam surfaces using a commercial adhesive in order to combine the composite sandwich panel. The low-velocity impact tests are performed to the sandwiches with the combination of two different magnesium (Mg) alloy foams (having 10 pores per inch (ppi) and 20 pores per inch), and carried out by a drop test machine with different values of impact velocity ranging from 1 to 10 m/s in order to analyse its effect. The main results of the impact tests are: force-displacement curves, peak force values, absorbed energy and influence of impact velocity.

Honeycomb sandwich structures are increasingly used in the automotive, aerospace and shipbuilding industries where fuel savings, increase in load carrying capacity, vehicle safety and decrease in gas emissions are very important aspects. The aim of this study was to develop the theoretical methods, initially proposed by the authors and by other researchers for the prediction of low-velocity impact responses of sandwich structures. The developed methods were applied to sandwich structures with aluminium honeycomb cores and glass-epoxy facings for the assessment of impact parameters and for the prediction of limit loads. The values of model parameters were compared with data reported in literature and the predictions of the limit loads were validated by means of the experimental data. Good achievement was obtained between the results of the theoretical models and the experimental data. The failure mode and the internal damage of the sandwich panels have been investigated using 3D computed tomography, which allowed the evaluation of parameters of energy balance model, and infrared thermography, which allowed the detection of the temperature evolution of the specimens during the tests. The experimental and theoretical results demonstrated that the use of glass-epoxy reinforcement on aluminium honeycomb sandwiches enhances the energy absorption and load carrying capacities.

The joining techniques of lightweight and strong materials in the transport industry (e.g. automotive, aerospace, shipbuilding industries) are very important for the safety of the entire structure. In these industries, when compared with other joining methods, the use of adhesively bonded joints presents unique properties such as greater strength, design flexibility, and reduction in fuel consumption, all thanks to low weight. The aim of this study was the analysis of the tensile fatigue behavior of adhesively bonded glass fiber/epoxy laminated composite single-lap joints with three different specimen types including 30, 40 and 50mm overlap lengths. In this study, composite adherents were manufactured via vacuum-assisted resin transfer molding and were bonded using Loctite 9461A&B toughened epoxy adhesive. The effect of a surface treatment method on the bonding strength was considered and it led to an increment of about 40%. A numerical analysis based on a finite element model was performed to predict fatigue life curve, and the predicted results showed good agreement with the experimental investigation.

The use of dental implants to solve different problems in dentistry has been growing rapidly. The success rates of dental implants are also very important for patients. Depending on the bone level of patients, short dental implants are very popular and widely used by many dentists. Although many dentists are using short dental implants frequently, It can be guessed that there can be stability problems because of crown to implant ratios. In this study, it is aimed to find out the effects of dental implant and abutment lengths on stability of short dental implants. 3 different short dental implant design made with the use of Solidworks 2013. Abutment lengths were 3,5 mm, 4 mm, 4,5 mm, 5 mm and implant lengths were 5 mm, 6 mm, 7 mm for each model. Human mandible model is transferred from Computed Tomography. Then, each implant model is mounted to modeled mandible and Finite Element Analysis is performed for each model. In order to see the effects of implant number on stability, we performed same analysis by placing 4 implants to the mandible

I n this article, a new design method, called Particle Swarm Optimization PSO , is used for the determination of PID control parameters; this is designated for the controlling of the speed and the position of the AC servomotor. For the determination of the decision parameters AC servomotors are mathematically modelled. Rise time, settling time, and overshoot are taken into consideration, during the optimization process. Controller’s performance is determined based on different criteria, such as, ITAE Integral of Time Weighted Absolute Error , IAE Integral of Absolute Error , ISE Integral of Squared Error and ITSE Integral of Time Weighted Squared Error . Superiority and accuracy of the proposed technique was verified by simulation results. In addition, considering the quality of the obtained results, proposed technique is found effective and strong in reduction of the error of motion control systems

The use of sandwich structures combines low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry), where the “lightweight design” philosophy and the safety of vehicles are very important aspects. The goal of this paper was the analysis of the bending and the low - velocity impact response of aluminium foam sandwiches reinforced by the outer skins made of glass fibre reinforced epoxy matrix. The results were compared with those obtained for aluminium foam sandwiches without glass fibre skins. An analytical model for the peak load prediction under low velocity impact was developed and the predicted values are in good agreement with the experimental measurements. The impact response of the sandwiches was investigated using a theoretical approach, based on the energy balance model and the model parameters were obtained by the tomographic analyses of the impacted panels.

Athermal elastic stress analysis of steel fiber reinforced aluminum laminated composite plate is investigated. Four sides of the composite plate are clamped and subjected to a uniform temperature load. The analysis is performed both analytically and numerically. Laminated composite is manufactured via hot pressing method. The investigation of the effects of the orientation angle is provided. Different orientation angles are used such as [0°/90°]s, [30°/-30°]s, [45°/-45°]s, and [60/-60]s. The analytical solution is obtained via classical laminated composite theory and the numerical solution is obtained by applying finite element method via ANSYS. Keywords—Laminated Composites, Thermo Elastic Stress, Finite Element Method.

The goal of this study was the analysis of the flatwise and edgewise compression response of closed-cell aluminium foam reinforced by the outer skins made of glass fiber reinforced epoxy matrix and the results were compared with those obtained for aluminium foams without glass fiber skins. Aluminium foams were produced by powder metallurgy method. Glass fiber skins were produced in various orientation angles in order to investigate their effects to the efficiency and capacity of absorbing energy of the sandwich. Glass fiber skins were bonded onto the aluminium foam core by epoxy resin in order to fabricate sandwich panels. As a result, the sandwich panels produced has particular importance for transport industries, such as automotive, aerospace, ship structures.

The goal of this research was the analysis of edgewise bending response of sandwiches, which consists of aluminium honeycomb sandwich reinforced by outer skins made of glass fiber reinforced epoxy matrix. The test results at different values of support span distances in terms of peak loads and absorbed energy were compared with those obtained by flatwise bending tests and by similar tests on aluminium honeycomb sandwiches without outer skins. The failure mechanisms have been also investigated. The experimental results presented that the sandwiches in the edgewise position failed at a higher load with less deflection compared to the specimens tested in the flatwise position. The current work has an important role in several areas, such as transport industry, in which lightweight structures with high capacity of energy dissipation is required.

Dental implant restoration has been widely accepted as one of the treatment modalities to replace missing teeth and to restore human masticatory function. The finite element method (FEM) has been a useful tool in studying the bone-to-implant interface under mechanical loading. The use of short dental implants are increased thanks to its advantages according to long dental implants when the quality of bone is lower. The aim of this study was to analyse the effects of implant diameter, length and loading conditions on short dental implants. A three dimensional (3D) model of short dental implants were made with different sizes and types. Dental implant designs were performed on Solidworks 2013. The mandible model is obtained from Computed Tomography then transferred to 3D model. Finite Element analysis is done by applying material properties, contact properties, physiological loading and boundary conditions with the use of Ansys Workbench

A numerical method for obtaining displacements and stresses in composite plates is presented. Mechanical behavior of steel fibre reinforced aluminum metal matrix composite plate is determined with elasto-plasticity. Experimental methods are used for obtaining mechanical properties of composite structure and finite element method is used for stress analysis. Stress distributions for different orientation angles are calculated using finite element analysis. Manufacturing techniques are compared. Minimal stress and yielding regions are specified.

In this paper, a virtual education environment is created in order to give students a better understanding of robot arm and a type of scara robot arm mechanism. Theorical informations are given students about robot and robotics applications by developed platform. For virtual laboratory applications, Visual Basic are used. The six-axis robot arm application which is similar to industrial formis provided by the improved software. Angular control prosess of robot arm is transferred to the virtual environment. It is shown, in animation, how the robot arm is directed by entering angle value. The entered value of angle is required in a certain range. When you exit out of this range, the robotic arm may be damaged. This platform will help students who recieve robot and robot arm education to understand matter of subject visually. This study will provide computer based robotic arm training for students who do not have access to necessary equipments and hardware. This study also can be used, as a supplementary training guide, by students who access necessary equipments and hardware. Keywors: Visual Basic, computer based robotic, robot arm;