An interpretative structural modeling based network reconfiguration strategy for power systems

The network reconfiguration is an important stage of restoring a power system after a complete blackout or a local outage. Reasonable planning of the network reconfiguration procedure is essential for rapidly restoring the power system concerned. An approach for evaluating the importance of a line is first proposed based on the line contraction concept. Then, the interpretative structural modeling (ISM) is employed to analyze the relationship among the factors having impacts on the network reconfiguration. The security and speediness of restoring generating units are considered with priority, and a method is next proposed to select the generating unit to be restored by maximizing the restoration benefit with both the generation capacity of the restored generating unit and the importance of the line in the restoration path considered. Both the start-up sequence of generating units and the related restoration paths are optimized together in the proposed method, and in this way the shortcomings of separately solving these two issues in the existing methods are avoided. Finally, the New England 10-unit 39-bus power system and the Guangdong power system in South China are employed to demonstrate the basic features of the proposed method.     

A novel function-structure concept network construction and analysis method for a smart product design system

The rapid growth of data and the requirement of designers to track massive data to obtain design stimuli have posed challenges to conceptual design, thereby promoting the development of data-driven design. Concept networks precisely capture design information from a large volume of unstructured and heterogeneous textual data and saliently decrease time and labor cost for designers to read texts, which creates new opportunities for developing a smart product design system. To advance data-driven design, this study proposes the novel function-structure concept network (FSCN) construction method, which combines sentence parsing and word/phrase extraction to integrate functional and structural information. Furthermore, a network analysis method is proposed to explore design information associations that contain both explicit and implicit associations together and thereby recommend them simultaneously to designers as inspirational stimuli to support design ideation. This approach can enhance designers' capabilities to build associations between design information, conceive new design ideas during conceptual design, and increase creativity for solving design problems. The proposed FSCN construction and analysis method can be used as an auxiliary tool to visualize associations among design information so as to inspire idea generation in the early stage of conceptual design. An illustrative example was used to validate the practicability of the proposed methodology. The code of the proposed method is available at https://github.com/KWflyer/FSCN.     

Engineering knowledge formalization and proposition for informatics development towards a CAD-integrated DfX system for product design

Target design methodologies (DfX) were developed to cope with specific engineering design issues such as cost-effectiveness, manufacturability, assemblability, maintainability, among others. However, DfX methodologies are undergoing the lack of real integration with 3D CAD systems. Their principles are currently applied downstream of the 3D modelling by following the well-known rules available from the literature and engineers’ know-how (tacit internal knowledge).This paper provides a method to formalize complex DfX engineering knowledge into explicit knowledge that can be reused for Advanced Engineering Informatics to aid designers and engineers in developing mechanical products. This research work wants to define a general method (ontology) able to couple DfX design guidelines (engineering knowledge) with geometrical product features of a product 3D model (engineering parametric data). A common layer for all DfX methods (horizontal) and dedicated layers for each DfX method (vertical) allow creating the suitable ontology for the systematic collection of the DfX rules considering each target. Moreover, the proposed framework is the first step for developing (future work) a software tool to assist engineers and designers during product development (3D CAD modelling).A design for assembly (DfA) case study shows how to collect assembly rules in the given framework. It demonstrates the applicability of the CAD-integrated DfX system in the mechanical design of a jig-crane. Several benefits are recognized: (i) systematic collection of DfA rules for informatics development, (ii) identification of assembly issues in the product development process, and (iii) reduction of effort and time during the design review.     

半柔性路面水泥砂浆配合比研究

水泥砂浆作为半柔性路面的重要组成部分,采用正交试验法对其进行了配合比设计,提出了改进跳桌法测定砂浆流动度,并检测了各配合比水泥砂浆抗压、抗折强度。在试验基础上综合考虑了水泥砂浆的流动性和抗压、抗折强度要求,给出了当前试验条件下半柔性路面水泥砂浆的最佳配合比。     

Modelling complex progressive failure in notched composite laminates with varying sizes and stacking sequences

The emergence of advanced computational methods and theoretical models for damage progression in composites has heralded the promise of virtual testing of composite structures with orthotropic lay-ups, complex geometries and multiple material systems. Recent studies have revealed that specimen size and material orthotropy has a major effect on the open hole tension (OHT) strength of composite laminates. The aim of this investigation is develop a progressive failure model for orthotropic composite laminates, employing stepwise discretization of the traction–separation relationship, to predict the effect of specimen size and laminate orthotropy on the OHT strength. The results show that a significant interaction exists between delamination and in-plane damage, so that models without considering delamination would over-predict strength. Furthermore, it is found that the increase in fracture toughness of blocked plies must be incorporated in the model to achieve good correlation with experimental results.     

“Measurement” and related concepts. Their interpretation in the VIM

The paper comments on the definitions of such terms as “measurement,” “nominal property,” “metrological traceability,” and others given in the 3-rd edition of International Vocabulary of Metrology (VIM). Proposals are offered for amendments to the terminology of the next edition of the VIM, taking into account new fields where measurements are applied.     

High sensitivity nanostructure incorporated interdigital silicon based capacitive accelerometer

Interdigital structures are realized on silicon substrates with high sensitivity to acceleration. The process employs a combination of anisotropic back-side micromachining with front-side vertical deep reactive ion etching of silicon. The incorporation of silicon-based nano-structures on the vertical planes of fingers leads to a significant increase in the capacitance of the device from 0.45 for simple planes to 40 pF for the nano-structured planes. Such structures show high sensitivity to inclination and accelerations, which could be due to field emission of electrons from nano-metric features. Around 8% change in the capacitance is observed upon a tilting sensor from 0° to 90° angle, which makes it proper for possible use as an earthquake sensor. A preliminary model for the capacitance and its dependence on the measurement voltage is presented.     

Modified relative arrival time technique for sizing inclined cracks

In this paper, a modified relative time technique is proposed for estimating the length and the orientation of inclined cracks using ultrasonic B-scan signals. The proposed technique utilizes the relative position of the tip diffraction echo to the corner reflection echo in an ultrasonic B-scan image to estimate the crack length and the crack inclination angle. Both finite element simulated signals and experimental signals, which are obtained from a specimen with a 3 mm crack with different inclination angles, are used to evaluate the estimation error of the proposed technique. The results show that the proposed technique overcomes the shortcoming of the conventional relative arrival time technique in sizing inclined cracks.     

Power harmonics analysis of programmable AC power source via variation semi-sinusoidal window

Harmonic contents are employed for indicating the quality of the programmable AC power source (PACPS). However, spectrum leakage usually occurs. This paper employs a variation semi-sinusoidal window (VSSW) for performing the power harmonic analysis. Since the rolloff of the sidelobes of the VSSW is fast, experimental results show that the VSSW outperforms existing windows.