Applied Mechanics and Materials Vols. 101-102

Abstract: The general mathematical model of internal meshing spiral bevel gears for nutation drive is studied. Based on conventional enveloping theory and transmission principle, the meshing of two spiral bevel gears in nutation drive was substituted by the meshing of an imaginary rotating crown gear engaging with the external and internal bevel gear respectively. The general mathematical model of crown gear was established. Then the general mathematical model of internal meshing spiral bevel gears is obtained by matrix transformation, which is suitable for a variety of gear tooth profiles. Finally, the mathematical model and 3D modeling of double circular-arc spiral bevel gears are developed.

Abstract: In this paper, we study stability analysis and stabilization problems for a class of nonlinear two-dimensional (2-D) discrete systems with time-varying state delays, described by local state-space (LSS) Fornasini-Marchesini (FM) second model. The upper and lower bounds of time-varying state delays are positive integers and the nonlinearity satisfies Lipschitz condition. First, a stability criteria is proposed through introducing a new Lyapunov function. Then a dynamic output feedback controller is designed to assure the stability of nonlinear 2-D time-varying systems. Moreover, the output feedback system matrices can be obtained by solving linear matrix inequalities (LMIs). Finally, a numerical example is given to demonstrate the effectiveness of our results.

Abstract: Design evaluation is necessary and important for conceptual design because it is often a must for designers to select a design concept from a number of candidates for further development. Assembly devices are usually product specific and there need extensive efforts in developing a feasible conceptual design solution satisfying a number of design constraints. To get a suitable evaluation method for assembly devices in the conceptual design phase, it’s necessary to apply Fuzzy mathematics in the evaluation method and the corresponding algorithm. This paper proposes a fuzzy index evaluation method for the conceptual design of assembly devices, where a number of evaluation indexes specific for assembly devices are proposed and organized into various levels for the evaluation algorithm. Finally, an evaluation software platform is presented, together with a simple design case study to illustrate the application of the proposed evaluation methodology.

Abstract: In accordance with the feature of non-linear and time varying for parameters that in the process of molecular distillation extract fructus schisandrae, intelligent logic control algorithm for temperature control in molecular distillation was proposed. The temperature deviation of molecular distillation and its deviation variety rates was applied as a feedback signal, the intelligent logic control rule was established. The test results show that the control of temperature for wiped film type molecular distiller with the method of this paper is simple, practical, and the control accuracy is improved, can very well solve the temperature control in molecular distillation.

Abstract: Planetary gear reducer with two internal gear pairs is known as NN type reducer. It has the advantage of large transmission ratio. Through the deep comprehensive studies on transmission ratio from four NN type reducers with different structure, the author proposes a new method to analyze transmission ratio from the tooth number difference for both internal gear pairs and external gear pairs, reveals rule, feature and range of transmission ratio of NN type reducer, and provides a clear train of thought for the selection of transmission ratio.

Abstract: This paper puts forward a neural network algorithm in pile integrity test on the basis of field data and the strengths of genetic algorithm and neural network algorithm. The result proves that it has faster convergence speed than simple BP algorithm, which can avert the artificial intervention during the data handling procedure and improve the reliability of the test result.

Abstract: A non-contact ultrasonic system to monitor the yogurt fermentation process through a stainless steel reactor wall is described. During the process, the acoustic impedance was determined by using multiple reflections of ultrasound within the stainless steel wall. Thus, the wall was part of the measurement system. By basing on measurement multiple reflections, the instrument sensitivity is increased by the power of the reflection coefficient. Experimental results show that the acoustic impedance changes continuously while pH declines. It is very useful, especially on production scale for yogurt that the acoustic impedance measurement does not demand a liquid transparent to ultrasound. Also, this noncontact sensing method can reduce the risk of food contamination from measuring instrument, and contribute to hygienization for food manufacture industries.

Abstract: Currently both Science & Engineering students and Art students are recruited by the major of Industrial Design at colleges and universities. This paper attempts to analyze their differences and similarities in terms of the student sources, theory and practice teaching system and employment status by a three-phase research, including pre-training, in-training and post-training. Based on the research results, a talent cultivation scheme is proposed for training of creative, contemporary and practical industrial designers, whereby the major has to combine the technique education with the aesthetic education, so as to establish a scientific and complete system of both theory and practice training.

Abstract: Because of its excellent power and economy in fuel, diesel is widely applied in recently years. Engine manufacturers are facing increasingly severe emission standards due to environmental concerns and desire for more efficient conversion from chemical energy to mechanical power. The crank linkage is one of the most important components of engine. It endures complex and various impact loads and it is the key point and difficulty of the engine design. The traditional design and analyze methods are so simple that they can not be satisfied with the actual demands, but the development of the reverse engineering and modeling software make possible that the response of crank linkage can be analyzed precisely. This paper has researched the combustion process in IC engine using the technology of computer simulation. Numerical modeling and experiment have been carried out on the diesel engine.

Abstract: Belt conveyors are the major equipments for bulk material transportation.This paper analyses the static and dynamic behaviours of the belt, and establishes the dynamic elastic modulus. By analyzing the characteristics of the Kelvin and Maxwell viscoelastic model, the former is selected as the conveyor belt model as it can more realistically reflect the mechanical characteristics of the conveyor system. This paper introduces the development of the belt conveyor, and analyzes the current research situation at home and abroad.