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The purpose of this paper is to explore the basic loading state in local loading forming process of large-sized complicated rib-web component, which is important for understanding process characteristic, controlling metal flow and designing preformed geometry of the local loading forming process. Moreover the analytical models for different loading states are established to quickly predict the metal flow.

Through analysis of geometric characteristic of large-sized complicated rib-web component and the deformation characteristic on planes of metal flow by local loading method, a representative cross-section is put forward and designed, which could reflect the local loading forming characteristics of large-sized complicated rib-web component. Finite element method (FEM) is used to analyze the stress and metal flow, and the analytical models of metal flow are established by using slab method (SM).

Three local loading states and one whole loading state are found in the local loading forming process of representative cross-section. Further, four loading states also exist in local loading forming process of large-sized complicated rib-web components. With the metal distribution in the process, some local loading states may turn into whole loading state. For the representative cross-section, the relative error of metal distribution between SM and FEM results is less than 15 per cent, and the relative error of metal in the rib cavity between SM and FEM results is less than 10 per cent.

Metal flow can be controlled by adjusting the loading states in the process. According to the metal flow laws in different loading states, a simple unequal-thickness billet can be designed to achieve initial metal distribution, and then, the secondary metal distribution can be achieved in the process.

Describes preliminary structural design work on a notional uninhabited tactical aircraft (UTA), carried out at Cranfield University. UTAs are seen as an important future element of military fleets. A notional baseline requirement was derived, leading to the evolution of a design solution. The basic requirements for such a UTA are naturally highly classified but, although industry has been hesitant to comment, the baseline requirements and design solution developed herein are believed to be reasonable.

The purpose of this study is to develop an efficient numerical procedure for simulating the effect of printing orientation, as one of the primary sources of anisotropy in 3D-printed components, on their fracture properties.

The extended finite element method and the cohesive zone model (XFEM-CZM) are used to develop subroutines for fracture simulation. The ability of two prevalent models, i.e. the continuous-varying fracture properties (CVF) model and the weak plane model (WPM), and a combination of both models (WPM-CVF) are evaluated to capture fracture behavior of the additively manufactured samples. These models are based on the non-local and local forms of the anisotropic maximum tangential stress criterion. The numerical models are assessed by comparing their results with experimental outcomes of 16 different configurations of polycarbonate samples printed using the material extrusion technique.

The results demonstrate that the CVF exaggerates the level of anisotropy, and the WPM cannot detect the mild anisotropy of 3D-printed parts, while the WPM-CVF produces the best results. Additionally, the non-local scheme outperforms the local approach in terms of finite element analysis performance, such as mesh dependency, robustness, etc.

This paper provides a method for modeling anisotropic fracture in 3D-printed objects. A new damage model based on a combination of two prevalent models is offered. Moreover, the developed subroutines for implementing the non-local anisotropic fracture criterion enable a reliable crack propagation simulation in media with varying degrees of complication, such as anisotropy.

The purpose of this paper is to discuss the calculation problem of the real carrying capacity of slewing bearings. The selection of slewing bearing to heavy-duty machine according to catalogue carrying capacity and also according to locally determined real carrying capacity is insufficient and it can be the cause of the damage of machine during exploitation.

The concepts of the local, total and general capacities is defined. The general capacity is a logical product of the local capacities. It is particularly useful in an analysis of slewing bearings incorporated into machines with complex structures. The FEM is applied in computations. The formation method of the mathematical model of a bearing is presented.

The computations of the local capacities and general capacity of a bearing for the limiting load of the bearing traces and the limiting tension of the bolts fastening the bearing were carried out. Considerations were illustrated by an example of the bearing of a mobile crane.

The paper presented in the methodology of the calculation of general bearing carrying capacity and the obtained results of calculations can be used already by designers of bearings and machine engines to elimination of the potential damages of machine on the stage of projecting.

The general capacity of a bearing into machines with complex and irregulars structure is considerably lower than the bearing catalogue capacity and then the local teal capacity. The reasons for the differences between the catalogue capacity and the general capacity of slewing bearings were given.

Calculations have been carried out on two elliptic wings, with ratios of major to minor axis 2·5 and 5 to 1 respectively, in order to demonstrate the use of vortex lattice theory in calculating lr and nr by lifting plane theory for wings of arbitrary plan form. Special tables of downwash, required in order to allow for the curvature of the wake, are included, and the origin of the formulae by which these are derived in a form applicable to linear theory is fully described. For the first wing, the calculated results for lr and nr and for local aerodynamic centre, load coefficients, and local lift coefficients are given for the Glauert‐Wieselsberger lifting line solution as well as for lifting plane solutions with three, six and nine control points respectively. The main work on the second wing is concerned with a six‐point lifting plane solution. The results show that there is not a serious difference between lifting line and lifting plane theory, excepting that the former does not give reliable values for the local a.c. For straight wings the six‐point lifting plane solution gives excellent accuracy. The method is applicable to wings of arbitrary plan, but the field of sweptback wings is unexplored and it should not be assumed without check that the relation of accuracy to number of control points is always the same. A further investigation is also required on the formula for nr when sweepback is present. The calculated value of lr for the 5 to 1 elliptic wing is in close agreement with the measured value for this wing obtained by Wieselsberger on a whirling arm. The report is concerned mainly with the calculation of spanwise load grading and local aerodynamic centre, and extension to detailed pressure distribution may require the use of more variables.

The properties of materials under impact load are introduced in terms of metal, nonmetallic materials and composite materials. And the application of impact load research in biological fields is also mentioned. The current hot research topics and achievements in this field are summarized. In addition, some problems in theoretical modeling and testing of the mechanical properties of materials are discussed.

The situation of materials under impact load is of great significance to show the mechanical performance. The performance of various materials under impact load is different, and there are many research methods. It is affected by some kinds of factors, such as the temperature, the gap and the speed of load.

The research on mechanical properties of materials under impact load has the characteristics as fellow. It is difficult to build the theoretical model, verify by experiment and analyze the data accumulation.

This review provides a reference for further study of material properties.

1. IN R. & M. 2596 and another report, the I latter concerned mainly with compressibility effects, the writer has considered the aerodynamic loading due to incidence of a number of wings of varying aspect ratio and sweep‐back. The information given in these reports was obtained by the use of a lattice of vortices for the computation of downwash and by the subsequent determination of the constants in the equation representing the vortex sheet. It is well known that the potential solutions obtained by this simplified representation are not necessarily of more than moderate accuracy when applied to problems in which wing thickness and viscosity are present, and those published have not been carried to a degree sufficient to give accurate detailed pressure distribution in the region of a discontinuity. It has, however, been shown in a later report on the measurement of pressure distribution at the surface of a sweptback wing that the accuracy as regards spanwise load grading and local aerodynamic centre is surprisingly good and it has been thought well worth while to extend the range of information provided in the above reports before proceeding to the more complex task of computing the detailed pressure distribution at the surface of a wing with allowance for viscosity.

Preparation of bibliographic data for the production of CD‐ROM public access catalogs (PACs) requires several services: merging records from various vendors or libraries, the elimination of duplicate records, the identification and decoding of holdings information, updating the database (often in an offline mode), and authority control. The nature of specific CD‐ROM catalogs affects the priorities for processing the database. For example, some systems exploit controlled vocabulary and cross references, making subject authority critical. Others provide powerful Boolean searching on key words derived from all parts of the bibliographic record; as a result, the need for quality control checks beyond those typically provided by library vendors is increased. This article identifies the services and processes offered by seven vendors that provide CD‐PACs and one vendor that processes MARC bibliographic databases.

The second part of a two‐part article presenting the computer program NCSA Mosaic which is a navigational tool for use with the World Wide Web, a system in widespread use over the Internet. Mosaic runs under Microsoft Windows. Describes the Mosaic interface, menus and options and gives guidelines on using them effectively. Reprinted from The World‐Wide Web, Mosaic and More by Jason J. Manger.

THIS is the type of panel which has received most attention from investigators and the critical load for local wrinkling of a single skin of thickness t is most simply expressed as