Advanced Materials Research Vol. 544

Abstract: This paper presents the composition and working principle of a intelligent irrigation system, and studies the reliability of system. It analyzes the system's failure modes. It establishes the system simulation model by using fault tree analysis, and it uses Monte Carlo method to carry on reliability simulation. The simulation results are given. Some suggestions on improving and perfecting the system are put forward based on the results. The conclusions provide a reference for reliability and maintainability of intelligent irrigation system. It is of great significance to increase agricultural production.

Abstract: Engineering components and structures in service are generally subjected to the multiaxial complex loads. The approach of critical plane has been widely accepted by most researchers as the best method in the multiaxial fatigue research field. It can be used well in the constant multiaxial fatigue loads, but not in the complex loads. Basis on analyzing characteristics of shear strain on material planes, the concept of weight-averaged maximum shear strain plane is proposed. A procedure is presented to determine the critical plane under multiaxial random loading. The angle values of the planes that experience peak values of maximum shear strains are averaged by employing the weight function, which is assumed to take into account the main factors of influencing the fatigue behavior, e.g. fatigue damage. The proposed algorithm is applied to the multiaxial in- and out-of-phase experiments to assess the correlation between the weight-averaged maximum shear strain direction and the position of the experimental fatigue crack initiation plane.

Abstract: Thought and method in function reserving design is for realizing the volume-production of individual products, based on the attention of users' individualities. The function tree is built up according to the subdivision of the total function. On this foundation, the method requires all the leaves of the function tree evaluated on their individuation degree by calculating the opening degree, association degree and dependency between the factors and the intimacy and interest degree between function factors and users. According to the result of individual degree evaluation, a rank of individuation degree priority of them is listed to help to decide the proper factors to reserve. By this means, users can participate themselves into the procedure of design, meeting their own individual needs.At last of this paper, the realizability of the thought and method is statemented and a case of lamp design of this method is taken as an example to demonstrate the design procedure.

Abstract: Two important parameters of torispherical head that are (interior radius of spherical crown area) and r (interior radius of transition corner) have been optimized by the module of the large general-purpose finite-element software ANSYS, targeting the strength and stability of the head. This paper provides an optimized torispherical head, which improves the stability of the edge of the head with acceptable strength of the head. The procedure is generally applicable as a design tool for optimal design.

Abstract: This paper suggests a design space exploration method using Artificial Neural Networks and metamodeling to systematically reduce the design space to a relatively small region. This method consists of three major steps. Firstly, self-organizing maps is employed to analyze design variables and objective function(s) with the original samples as preliminary reduction optimization of the initial large design space. Successively, resampling within the preliminary reduction space, clustering sample points using the fuzzy c-means clustering method with the given number of cluster, and choosing the most attractive cluster to construct kriging model and identify the design optimum within the reduced design space in the last step. The accuracy and validity of proposed methodology is proved by a heat exchanger design problem. It is found that the proposed method can intuitively capture promising design regions in which it is efficient to acquire the global or near-global desigm optimum.

Abstract: Nowadays, computer-based engineering design is becoming widely used in the design of products. In the field of engineering, CAD model, FEM method and surrogate model are used to reduce the time and computational cost comparing with the traditional engineering design. But when facing with computationally expensive tasks, such design method mentioned above seems unable to deal with such tasks. In that case, surrogate model is gradually used and shows great potential in dealing with the computationally complex tasks. Although computing power and speed are rapidly growing, the use of the computer simulation analysis is limited in doing engineering design and some other analysis such as reliability analysis for complex product, so that it limits the use of metamodeling techniques. In that case, we use space-filling DOE sample method to support the construction of surrogate model. In this paper, we consider both Hammersley sequences and SVM as sampling method and surrogate model to construct the simulation design model, aiming at reduce computational costs. SVR achieves more accuracy and shows great potential in application in the design of complex and computationally expensive tasks.

Abstract: For probabilistic design problems with implicit limit state functions encountered in practical application, it is difficult to perform reliability analysis due to the expensive computational cost. In this paper, a new reliability analysis method which applies support vector machine classification(SVM-C) and adaptive sampling strategy is proposed to improve the efficiency. The SVM-C constructs a model defining the boundary of failure regions which classifies samples as safe or failed using SVM-C, then this model is used to replace the true limit state function,thus reducing the computational cost. The adaptive sampling strategy is applied to select samples along the constraint boundaries. It can also improves the efficiency of the proposed method. In the end, a probability analysis example is presented to prove the feasible and efficient of the proposed method.

Abstract: Biologic systems frequently have electric activity associated with them. This activity can be a constant dc electric field, a constant flux of charge-carrying particles or current, or a time-varying electric field or current associated with some time-dependent biologic or biochemical phenomenon. The mechanism of electric conductivity in the body involves ions as charge carriers. Thus, picking up bioelectric signals involves interacting with these ionic charge carriers and transducing ionic currents into electric currents required by wires and electronic instrumentation. Calcium ion is so important in our body, which plays a crucial role in metabolism.The common methods of detecting calcium ion include radioactive tracer method, activation shine protein method, etc, we choose calcium ion sensing needle as a tool to detect the calcium ion in the acupoint.

Abstract: Reliability-based design optimization (RBDO) evaluates variation of output induced by uncertainties of design variables and results in an optimal design while satisfying the reliability requirements. However, its use in practical applications is hindered by the huge computational cost during the evaluation of structure reliability. In this paper, the reliability index based decoupling method is developed to improve the efficiency of probabilistic optimization. The reliability index is used to calculate the shifting vector in the decoupling process, due to its efficiency in evaluating violated probabilistic constraints. The computation capability of the proposed method is demonstrated using two examples, which are widely used to test RBDO methods. The comparison results show that the proposed method has the same accuracy as the existing methods, and it is also very efficient.

Abstract: The Large-scale Laser Process Center (LLPC) is a type of Machine Tool (MT). With the LLPC as a sample, this paper analyzed the systemic factors of the MT product, built the Multi-Objective(MO) system impacting on the product design results, with the requires of MO proposed a integrated design method with a Frame Structure(FS), applied on the practical design of LLPC. By the verification from the process controlling and reality product, proved the expectation and the value of this method. It gave a reasonable guide for the structural design and cleared the product design confused stage, improved the design efficiency and the image quality of MT product, and indicated the main design process line in the product development.