Poonsak Pisek, Somchai Sessirisombat and Bunyong Rungroungdouyboon, "Biomechanical Evaluation of the Maxilla during Maxillary Distraction Osteogenessis with the New Hybrid Distraction Device: A Finite Element Analysis", Journal of the Medical Association of Thailand, V. 100, N. 8, August 2017, p s16-s23.
Background: Patients with cleft lip and palate (CLP), who have malocclusion combined with severe skeletal Class III problems, usually have multidimensional maxillary hypoplasia. The present study invented a new hybrid distraction device to correct severe skeletal problems.
Objective: To evaluate biomechanical of a new hybrid distractor device during maxillary sagittal distraction osteogenesis.
Material and Method: Three-dimensional finite element skull models of a 20-year-old, non-syndromic male patient with bilateral complete cleft lip and palate was constructed. Stress distributions and displacement of the new hybrid distractor were analyzed using ANSYS v.10.0.
Results: The maximum stress levels were observed for both external and internal components of the new hybrid distractor device. The values of maximum stress were not exceeding yield stress and the range of safety factor was 2.36 to 3.76. The maxilla bone was in equilibrium balance between action force and reaction force and showed symmetrical displacement.
Conclusion: The new hybrid distractor device has enough strength during maxillary distraction osteogenesis and can provide controlled symmetrical displacement of the maxilla.
T. Luckanawat, P. Kooncumchoo and B. Rungroungdouyboon, "Design and Development of the lower limb rehabilitation robot for restoration of normal gait in stroke patients", Journal of Research and Applications in Mechanical Engineering, Transactions of the TSME 2016, Nov 2016
This paper presents new machine of lower limb rehabilitation robot, called “TU Gait Trainer”. The machine has been developed for stroke patients to restore normal gait with trajectory and ankle angle control. While patients were being gotten physical therapy by TU Gait Trainer, their each foot was fastened by foot supporter of the rehabilitation robot and moved follow normal gait pattern by only 1 motor with linkage mechanism which was specific designed for normal gait pattern. During ankles had been moving, TU Gait Trainer was controlling angle of patient’s ankles to move in dorsiflexion and plantarflexion posture same as normal gait pattern also. TU Gait Trainer prototype had been made up and getting efficiency data with real patients. The testing results of real patients with TU Gait Trainer are presented. The results show patients got stronger muscle and they got chance to restore normal walking
Phadungsak Rattanadecho, Natt Makul, Aumpol Pichaicherd, Porncharoen Chanamai and Bunyong Rungroungdouyboon, "A novel rapid microwave-thermal process for accelerated curing of concrete: Prototype design, optimal process and experimental investigations", Construction and Building Materials, V.123, 2016, p 768-784
In this work, a mobile microwave (MW)-assisted curing unit for the accelerated curing of concrete workpiece
is designed based on coupled electromagnetic (MW)–thermal analysis. The design of this unit is described together with experimental investigations into the heating characteristics of concrete workpiece subjected to the MW-accelerated curing process. Mathematical models are applied to design a horn-shaped MW cavity and as a basis for constructing a stationary and a moving MW-accelerated curing unit that uses MW energy at an operating frequency of 2.45 ± 0.05 GHz and at powers of 400W and 800 W. The experiments included the effects of MW curing on the temperature evolution, moisture content variation, and compressive strength development properties of the concrete. Also, the concrete workpiece was compared to water-cured conventional concretes and air-cured conventional concretes on the basis of these properties. Based on the concept of antenna, a rectangular horn-shaped cavity of 246.7 mm wide 333.68 mm long is designed showing a uniform thermal distribution for concrete curing. From the experiments, it was found that the application period for curing using the mobile MW-curing unit was considerably shorter than for conventional curing methods. The appropriate preheating interval is 30 min, and MW energizing for 15 min/time and a paused duration of 60 min produces maximum compressive strength. However, the time needed for curing was considerable. When concrete was heated using MW energy for more than 90 min at over 80 C, the effect was a continuous decrease in compressive strength. Further, at early age, the compressive strength development of the concrete workpiece subjected to MW curing was greater than that achieved by air curing or water wet-curing.
Cholaseuk, D., Optimum Design of Disk Structure under Planar Loads,Thammasat International Journal of Sciences and Technology, Vol. 18, No. 4, October-December 2013
Disk structures under planar loads are commonly found in machines, such as disk brakes, automobile wheels, gears, etc. Weight reduction of such parts reduces inertia of the systems which helps in improving overall performance of the machines. In this research, a numerical method employing a stress-based material distribution scheme is utilized in the design of disk structures. During the process, stress distribution is calculated by finite element method. Then, elements with low stress are successively removed. The iteration process continues until the optimum topology is revealed. It is observed that the optimum topology follows the pattern of the corresponding principal stress trajectories. The resulting designs for different conditions provide a basic guideline for the optimum topology which can serve as a starting point for creating solid models for optimum shape design of disk structures.