Applied Mechanics and Materials Vols. 26-28

Abstract: This study deals with an application of the method of the coefficient of variation in strength prediction of the self-piercing riveted joints. Defined as the ratio of the standard deviation to the mean, the coefficient of variation may be used in both the reliability-based design of self-piercing riveted joints and in the evaluation of existing products. In this study, the concept and definition of the coefficient of variation are stated. The procedure of the use of coefficient of variation for approximate calculations of strength of the self-piercing riveted joints is presented and compared with the classical Taylor expansion method. This is illustrated with a numerical example.

Abstract: Low carbon steel sheets are used invariably in automobile body panels and construction structural applications. Conventional forming techniques require forming dies and heavy duty presses to make required shapes, which are costly in manufacturing. Incremental forming is a recently developing die less sheet metal part production technique in which the necessary part is obtained by gradually tracing its contours on a sheet of required thickness using stepwise tool indents. In this investigation, Low carbon steel sheets of different thicknesses were incrementally formed using a hemispherical tool under varying step depths. The final thickness of the sheet, forming angle, roughness and microhardness of the formed shapes were characterized. The microstructure of the formed materials was studied using optical microscope.

Abstract: Ontology is the basis of knowledge modeling on the Semantic Web, and fuzzy ontology is an extension of domain ontology for solving the uncertainty problems. Ontology-base knowledge modeling of product data management (PDM) is meaningful for product design and trade etc. In order to handle fuzzy phenomenon and uncertainty of product knowledge, this paper proposes a series of fuzzy ontology models that consists of fuzzy domain ontology and fuzzy linguistic variable ontologies. Then, a fuzzy ontology framework is presented, including three parts: concepts, properties of concepts and values of properties. The application, which uses fuzzy ontology to model product knowledge, shows that these models can overcome the localization of other fuzzy ontology models, and this research facilitates the fuzzy knowledge sharing and reuse for PDM on the Semantic Web.

Abstract: The paper introduces the shrinkage center conception and simplified model of the material solidification. Starting with a micro unit, the paper builds the force model, and derives the formula of the stress-strain principles on the basis of the force balance function, relationship between the strain and displacement and the unit boundary conditions. The theoretic analysis reveals the influence factors and the quantitative expression affecting parts deformation. At last, two special cases, separating layers and complete adhesive layers, are discussed to display the stress-strain distribution under such conditions.

Abstract: Nano-Fe particles were selected as microwave-absorber, and added in the epoxy resin. Epoxy resin/nano-Fe composite materials were cured by microwave irradiation and heating. Vector network analysis, dynamic mechanical analysis(DMA) and scanning electron microscope(SEM) were used to study the curing behaviors of composite materials under the different curing ways. Results show that the dielectric constant(εr) and the dielectric loss factor(tanδ) of the epoxy resin increased obviously when nano-Fe particles were added, and microwave absorption properties of epoxy resin/nano-Fe composite materials improved greatly with increasing contents of nano-Fe particles. DMA results indicate that the storage modulus (E’) and glass transition temperature(Tg) of epoxy resin samples with nano-Fe particles were higher than those without nano-Fe particles. The microstructure and phase composition of the samples were studied by SEM and EDX. Results show that nano-Fe particles were homogeneously dispersed in the epoxy resin matrix under microwave irradiation, which implies improved strength and toughness of epoxy resin/nano-Fe composite materials.

Abstract: In view of those situations which follower of cam mechanism have complicated motion law in rise travel and return travel, basing on secondary development and applying synthetically of Pro/E, following the reverse turn principle of the tradition graphic method, the wholly parameterized design system was developed. Furthermore, virtual assembly and motion simulation had been realized. According to the parameter imported by the consumer, the system can generate automatically cam pitch curve and cam contour of 16 kinds of combination follower motion law. It can raise cam mechanism product design quality and efficiency.

Abstract: In this paper, we proposed a new approach to simulate the deformation of skeletal muscles based on bio-mechanical considerations. The musculo-tendon unit, which generates the active and passive force of the muscles to drive skeletal motion, is established according to the tension-length curve. Muscular deformation is achieved by embedding a musculo-tendon unit in the volume-preserving B-spline solid. The model provides suitable visual effect and manages the deformation of muscles on the basis of the bio-mechanical properties. We demonstrated the simulation by creating a musculoskeletal model of the upper limb.This document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.

Abstract: The three dimensional finite element model of composite laminates made of carbon fiber reinforced bismaleimide resin is built, and the stress state of the composite laminates under unidirectional tensile force is analyzed. The strength criterion and damage mode are given based on the stresses of material principal direction. The three dimensional finite element model of the same laminates with non-penetrating damage repaired by scarf bonding method is built, and the stress state is also analyzed. The strength criterion and the damage mode of the scarf bonding composite laminates are also given. The strength and the damage mode of original laminates are compared with that of the laminates with non-penetrating damage. The influence of the interlaminar stress is considered in these analysis models. It is showed that the three dimensional models can simulate the geometric and physical features of the real composite laminates. It is concluded that the original composite laminates made of carbon fiber reinforced bismaleimide resin and the repaired one both damage first in the laminar whose second material principal direction coincides with the axial tensile force. And the damage mode is resin crack under tensile stress. The strength of the bonding patches is higher than the laminates repaired by scarf bonding. After scarf bonding repair, the strength of the damaged laminates can recover up to about eighty-four percent.

Abstract: The technical nature of search engine in collecting and extracting mass internet information enables auto bidding advertisement based on search engine enjoys a powerful advantage beyond the rules of the game, compared with the advertisement of ordinary web page nature. However, because Internet and search engine is a newly developed matter with many of their behaviors drifting away outside the traditional government supervision and industry self-discipline, it has caused the frequent occurrence of unhealthy tendencies, provoking great dissatisfaction of society. It has become a must to effectively regulate auto bidding advertisement. The three aspects could be considered the starting points in terms of government supervision, industry self-discipline and social supervision. We shall not only insist on and perfect government supervision, but also strengthen the industry self-discipline for realizing organic entity of administrative supervision of government and management of industry self-discipline as well as organic entity of administrative review and self-discipline examination, offering useful references for perfecting the advertisement regulation mode of government leadership system in China. While guaranteeing a healthy and orderly development of search engine, our purpose is to render back an honest and clean searching environment of internet information to the public.

Abstract: Three turbulent models, standard k- model, realizable k- model and SST k- model, are proposed to calculate the distribution of the flow field in a novel static circulating jet mixer. The results show that the SST k-model can depict truly the fluid motion in the novel jet mixer from the velocity vector distribution. The k-Standard model overestimates k in the wall and the bulk zones. Comparing the numerical models, the SST k- model gives better results than the other k-models at the same Reynold number.