Search results

The purpose of this paper is to study the resonance failure sensitivity analysis of straight-tapered assembled pipe conveying nonuniform axial fluid by an active learning Kriging (ALK) method.

In this study, first, the motion equation of straight-tapered assembled pipe conveying nonuniform fluid is built. Second, the Galerkin method is used for calculating the natural frequency of assembled pipe conveying nonuniform fluid. Third, the ALK method based on expected risk function (ERF) is used to calculate the resonance failure probability and moment independent global sensitivity analysis.

The findings of this paper highlight that the eigenfrequency and critical velocity of uniform fluid-conveying pipe are less than the reality and the error is biggest in first-order natural frequency. The importance ranking of input variables affecting the resonance failure can be obtained. The importance ranking is different for a different velocity and mode number. By reducing the uncertainty of variables with a high index, the resonance failure probability can be reduced maximally.

There are no experiments on the eigenfrequency and critical velocity. There is no experiments about natural frequency and critical velocity of straight tapered assembled pipe to verify the theory in this paper.

The originality of this paper lies as follows: the motion equation of straight-tapered pipe conveying nonuniform fluid is first obtained. The eigenfrequency of nonuniform fluid and uniform fluid inside the assembled pipe are compared. The resonance reliability analysis of straight-tapered assembled pipe is first proposed. From the results, it is observed that the resonance failure probability can be reduced efficiently.

This paper deals with the organizing of interactive product development. Developing products in interaction between firms may provide benefits in terms of specialization, increased innovation, and possibilities to perform development activities in parallel. However, the differentiation of product development among a number of firms also implies that various dependencies need to be dealt with across firm boundaries. How dependencies may be dealt with across firms is related to how product development is organized. The purpose of the paper is to explore dependencies and how interactive product development may be organized with regard to these dependencies.

The analytical framework is based on the industrial network approach, and deals with the development of products in terms of adaptation and combination of heterogeneous resources. There are dependencies between resources, that is, they are embedded, implying that no resource can be developed in isolation. The characteristics of and dependencies related to four main categories of resources (products, production facilities, business units and business relationships) provide a basis for analyzing the organizing of interactive product development.

Three in-depth case studies are used to explore the organizing of interactive product development with regard to dependencies. The first two cases are based on the development of the electrical system and the seats for Volvo’s large car platform (P2), performed in interaction with Delphi and Lear respectively. The third case is based on the interaction between Scania and Dayco/DFC Tech for the development of various pipes and hoses for a new truck model.

The analysis is focused on what different dependencies the firms considered and dealt with, and how product development was organized with regard to these dependencies. It is concluded that there is a complex and dynamic pattern of dependencies that reaches far beyond the developed product as well as beyond individual business units. To deal with these dependencies, development may be organized in teams where several business units are represented. This enables interaction between different business units’ resource collections, which is important for resource adaptation as well as for innovation. The delimiting and relating functions of the team boundary are elaborated upon and it is argued that also teams may be regarded as actors. It is also concluded that a modular product structure may entail a modular organization with regard to the teams, though, interaction between business units and teams is needed. A strong connection between the technical structure and the organizational structure is identified and it is concluded that policies regarding the technical structure (e.g. concerning “carry-over”) cannot be separated from the management of the organizational structure (e.g. the supplier structure). The organizing of product development is in itself a complex and dynamic task that needs to be subject to interaction between business units.

This paper aims to present the approximate limit pressure solutions for thin-walled shape-imperfect 90° pipe bends. Limit pressure was determined by finite element (FE) limit analysis with the consideration of small geometry change effects.

The limit pressure of 90° pipe bends with ovality and thinning has been evaluated by geometric linear FE approach. Internal pressure was applied to the inner surface of the FE pipe bend models. When von-Mises stress equals or just exceeds the yield strength of the material, the corresponding pressure was considered as the limit pressure for all models. The current FE methodology was evaluated by the theoretical solution which has been published in the literature.

Ovality and thinning produced a significant effect on thin-walled pipe bends. The ovality weakened pipe bend performance at any constant thinning, while thinning improved the performance of the bend portion at any constant ovality. The limit pressure of pipe bends under internal pressure increased with an increase in the bend ratio and decreased with an increase in the pipe ratio. With a simultaneous increment in bend radius and reduction in wall thickness, there was a reduction in limit pressure. A new closed-form empirical solution was proposed to evaluate limit pressure, which was validated with published experimental data.

The influences of structural deformation (ovality and thinning) in the limit pressure analysis of 90° pipe bends have not been investigated and reported.

To provide information on the distribution of oil deposition inside the pipe conducting oil mist used for lubricating purposes and to show resulting variations of oil/air ratio.

The model of an industrial pipeline has been assembled ranging more than 100 m away from the oil mist source, equipped with devices collecting oil deposited inside the pipes. Other tests were performed in stands constructed as parts of pipes coiled in helical form. Long time experiments with continuous oil mist flow enabled to achieve calculable results.

The quantitative results obtained in experimental investigation on the reduction of oil/air ratio in an oil mist header system show that considerable differences of the oil/air ratio may be observed in a typical long pipeline. Possible consequences of oil deficiency on lubrication of remote mechanisms are presented in the case study. Results of tests are shown in diagrams and tables. These results may be useful for correction of design calculations procedures.

Tests have been made on the basis of one kind of the oil atomized in typical condition and conveyed with steady flow through the piping of rather simple geometry. However, there are other factors affecting oil droplets deposition and the most influencing are probably: the flow velocity/pipe diameter factor, oil atomization characteristics and the geometry of the oil mist piping.

The research has shown dramatic decrease of oil content in the long distance systems that may result in poor lubrication of remote mechanisms or over lubrication of those located close to the oil mist generator. It should be taken on account in calculation of oil mist demand to particular lubrication points.

Presented tests have been carried in the scale and flow parameters very close to those applied in industry. Thus, the results are reliable and could be very useful both for designers and the practitioners of centralized oil mist systems.

The purpose of this study is to develop a robot for non-destructive testing of the pipelines to improve its reliability and reduce the loss of products due to cracks, corrosions, etc.

In this study, an inline inspection robot was developed for crack and corrosion detection in the pipeline. The developed robot consists of ultrasonic sensors to avoid obstacles, a visual aid with high resolution to view real time images and colour sensors for corrosion detection. The Autodesk inventor software was used for the drafting and solid modelling of the robot. A dummy pipe of 500 mm diameter and 2,000 mm length with induced cracks and corrosion was fabricated to test the robot. The colour sensors placed at each side of the robot were used to detect corrosion in the dummy pipe whilst the image processing was done to analyse the crack, as well as the type and depth of corrosion present in the dummy pipe.

The results obtained show the ability of the developed robot to detect cracks and determine the crack growth in the pipeline in addition to its ability to determine corrosion.

Hence, the study provides a diagnostic tool for detecting pipeline defects and analysing the extent of defects to determine the fatigue rate and the useful life of the pipeline.

The novelties of this study is based on the fact that it was designed to avoid obstacles and check for cracks, leakage and corrosion in pipelines autonomously. It has visual aid that makes it possible to see the interior of the pipe. This makes it easier to identify the defect and the location of the defects before a catastrophic failure. The device is also equipped with sensors, which can detect defects and send the signal to a control system, as well as a Bluetooth device so the operator can have real time information about the state and integrity of the pipelines. The system is also integrated with a Bluetooth device, which permits its compatibility with Android and other mobile applications. Thus, the enabled user can send a command to query the state of the pipeline at any location with the feedback received in the form of short message service. Hence, this study offers contribution in the development of an independent (self-governing) system with the capability to autonomously detect defects in pipe walls and effectively communicate feedback to the authorised users. The prototype model for the evaluation of pipeline integrity will bring about a more proactive way to detect pipeline defects so that effort can be geared towards its restoration before it becomes a major problem, which will subsequently affect productivity and incur losses.

A METHOD of joining pipes which does not make use of heavy bulky fittings has always been required in the aircraft industry. In addition, as aircraft speeds increase well into the supersonic range, the need for more reliable joints that will withstand even more rigorous working conditions becomes apparent.

Although constant research is being carried out for improvements in the manner of new techniques, materials and every sphere possible to afford the best protection that can be provided for every type and size of pipe against the problem of corrosion, whether such corrosion exists or forms internally or externally, or whether it takes the form of erosion of the pipe or as a build‐up of internal encrustation, it may be worth briefly summarising the details of at least one process of internal protection which has stood the test of time in a very definitive manner.

Of the thermoplastics group of materials, unplasticised polyvinyl chloride, commonly known as rigid PVC, appears to have made the slowest progress in the U.K. It was introduced here shortly after the war, but, as recently as 1958, the annual usage for industrial pipes was estimated at only 500 tons. In the same year, France, Holland and Italy processed approximately 4,000, 8,000 and 12,000 tons respectively. This article indicates the scope of the material in corrosive environments.

The factors governing the flow properties of grease are discussed with particular reference to the RN multipurpose grease XG‐274 and the soft lime‐base grease LG‐380. Results obtained at 70°F using a pumping rig with pipes of ½ inch, ¾ inch or ¼ inch external diameter are presented in terms of apparent viscosity in line with the procedure approved by the National Lubricating Grease Institute. The data can be used to assess the suitability of systems proposed for dispensing the greases, supplemented where necessary by apparent viscosity measurement by Standard Method ASTM‐D 1092.

Learning behaviors related to quality improvement in manufacturing systems (i.e. reduction of defectiveness over production cycles) are widely investigated. Many different approaches have been introduced to describe the link between the learning mechanism and quality performance of a plant. In a previous study by the same authors, a set of learning “composition laws” for two basic structures were defined to provide a tool to forecast the behavior of complex manufacturing systems composed by a network of elementary processes. This paper presents an empirical investigation about these learning composition laws on a real case in the field of automotive exhaust‐systems manufacturing.