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The purpose of this paper is to investigate the process of jamming of the hollow parts on the shaft and to derive a mathematical model for jamming in an assembly process.

The mathematical model for jamming of parts on the shaft in an assembly process is based on the sizes, geometry, angular declination of part and shaft axes, and the frictional factor.

The equation for angular positional tolerance of coaxial parts and shafts, based on their geometry and sizes and leading to jamming, was derived.

A mathematical model of parts jamming on the shaft is developed for assembly mechanisms. This research does not consider flexible deformations of components in assembly mechanisms, which results in the axis concentricity of part and shaft in the assembly process.

The results presented in the form of angular positional tolerance for coaxial parts and shafts based on their geometry and sizes make it possible to avoid the jamming of the parts. The results allow for formulating the angular positional tolerance of the assembly mechanisms that clamp the parts.

The proposed method for calculating the angular positional tolerance of coaxial parts and shafts for the assembly process should allow for increasing the reliability of the assembly process in the manufacturing industry.

The implied assembly constraints of a computer-aided design (CAD) model (e.g. hierarchical constraints, geometric constraints and topological constraints) represent an important basis for product assembly sequence intelligent planning. Assembly prior knowledge contains factual assembly knowledge and experience assembly knowledge, which are important factors for assembly sequence intelligent planning. This paper aims to improve monotonous assembly sequence planning for a rigid product, intelligent planning of product assembly sequences based on spatio-temporal semantic knowledge is proposed.

A spatio-temporal semantic assembly information model is established. The internal data of the CAD model are accessed to extract spatio-temporal semantic assembly information. The knowledge system for assembly sequence intelligent planning is built using an ontology model. The assembly sequence for the sub-assembly and assembly is generated via attribute retrieval and rule reasoning of spatio-temporal semantic knowledge. The optimal assembly sequence is achieved via a fuzzy comprehensive evaluation.

The proposed spatio-temporal semantic information model and knowledge system can simultaneously express CAD model knowledge and prior knowledge for intelligent planning of product assembly sequences. Attribute retrieval and rule reasoning of spatio-temporal semantic knowledge can be used to generate product assembly sequences.

The assembly sequence intelligent planning example of linear motor highlights the validity of intelligent planning of product assembly sequences based on spatio-temporal semantic knowledge.

The spatio-temporal semantic information model and knowledge system are built to simultaneously express CAD model knowledge and assembly prior knowledge. The generation algorithm via attribute retrieval and rule reasoning of spatio-temporal semantic knowledge is given for intelligent planning of product assembly sequences in this paper. The proposed method is efficient because of the small search space.

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.

The following classified, annotated list of titles is intended to provide reference librarians with a current checklist of new reference books, and is designed to supplement the RSR review column, “Recent Reference Books,” by Frances Neel Cheney. “Reference Books in Print” includes all additional books received prior to the inclusion deadline established for this issue. Appearance in this column does not preclude a later review in RSR. Publishers are urged to send a copy of all new reference books directly to RSR as soon as published, for immediate listing in “Reference Books in Print.” Reference books with imprints older than two years will not be included (with the exception of current reprints or older books newly acquired for distribution by another publisher). The column shall also occasionally include library science or other library related publications of other than a reference character.

The wear of different car parts is affected by a variety of external factors. Mechanical wear takes the greatest toll of moving surfaces. Minute as the particles which wear away are, in their total they are the essential factor which causes the surface structure, the original dimensions and the shape of the parts to change gradually. Moving parts are not the only ones to deteriorate from mechanical wear: stationary parts, such as connections by threads, wedges, slots, etc., also suffer heavily.

THE routine maintenance of aircraft undercarriages is an important function whether the aircraft is operated by large or small airlines, and it is a fact that these costly items start wearing from the very first day they are installed. The amount of wear that takes place on an aircraft undercarriage depends very much on the type of work on which it is employed. It will be obvious that aircraft on short runs take‐off and land very frequently and consequently show signs of wear sooner than those on long distance flights. Regular maintenance to the undercarriage parts will no doubt be carried out from the time the aircraft is delivered, as specified under the maker's maintenance manuals, but there will come a time when the permitted amount of wear has taken place and the undercarriage must be overhauled.

This characteristic is important enough in aircraft maintenance to be covered separately. Considerably less embrittlement than that in bath plating is realized in selective plating. With one proprietary solution, Cadmium LHE (Code SPS 5070), hydrogen embrittlement is almost negligible. Selectively plated nickel and nickel‐tungsten alloys also can be plated with so little hydrogen content that no baking for embrittle‐content that no baking for embrittlement relief is required.

The application of rapid prototyping in fabricating a non‐assembly, multi‐articulated robotic hand with inserts is presented in this paper. The development of robotic systems that have all necessary components inserted, with no assembly required, and ready to function when the manufacturing process is complete is quite attractive. Layered manufacturing, in particular stereolithography, can provide a means to do this. Stereolithography produces a solid plastic prototype via a manufacturing procedure where three‐dimensional solid models are constructed layer upon layer by the fusion of material under computer control. An important aspect of the rapid prototype method used in this research is that multi‐jointed systems can be fabricated in one step, without requiring assembly, while maintaining the desired joint mobility. This document presents the design and techniques for part insertion into a non‐assembly, multi‐articulated, dexterous finger prototype built with stereolithography.

This paper presents an investigation into residual stresses in selective laser sintering (SLS) and selective laser melting (SLM), aiming at a better understanding of this phenomenon.

First, the origin of residual stresses is explored and a simple theoretical model is developed to predict residual stress distributions. Next, experimental methods are used to measure the residual stress profiles in a set of test samples produced with different process parameters.

Residual stresses are found to be very large in SLM parts. In general, the residual stress profile consists of two zones of large tensile stresses at the top and bottom of the part, and a large zone of intermediate compressive stress in between. The most important parameters determining the magnitude and shape of the residual stress profiles are the material properties, the sample and substrate height, the laser scanning strategy and the heating conditions.

All experiments were conducted on parts produced from stainless steel powder (316L) and quantitative results cannot be simply extrapolated to other materials. However, most qualitative results can still be generalized.

This paper can serve as an aid in understanding the importance of residual stresses in SLS/SLM and other additive manufacturing processes involving a localized heat input. Some of the conclusions can be used to avoid problems associated with residual stresses.

Metal laser-powder-bed-fusion using laser-beam parts are particularly susceptible to contamination due to particles attached to the surface. This may compromise so-called technical cleanliness (e.g. in NASA RPTSTD-8070, ASTM G93, ISO 14952 or ISO 16232), which is important for many 3D-printed components, such as implants or liquid rocket engines. The purpose of the presented comparative study is to show how cleanliness is improved by design and different surface treatment methods.

Convex and concave test parts were designed, built and surface-treated by combinations of media blasting, electroless nickel plating and electrochemical polishing. After cleaning and analysing the technical cleanliness according to ASTM and ISO standards, effects on particle contamination, appearance, mass and dimensional accuracy are presented.

Contamination reduction factors are introduced for different particle sizes and surface treatment methods. Surface treatments were more effective for concave design features, however, the initial and resulting absolute particle contamination was higher. Results further indicate that there are trade-offs between cleanliness and other objectives in design. Design guidelines are introduced to solve conflicts in design when requirements for cleanliness exist.

This paper recommends designing parts and corresponding process chains for manufacturing simultaneously. Incorporating post-processing characteristics into the design phase is both feasible and essential. In the experimental study, electroless nickel plating in combination with prior glass bead blasting resulted in the lowest total remaining particle contamination. This process applied for cleanliness is a novelty, as well as a comparison between the different surface treatment methods.