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21 – 30 of over 5000
Article
Publication date: 1 May 1994

A. Corigliano

The finite element quasi‐static analysis of elastoplastic systemsis studied by making use of a generalized variable approach for the spatialdiscretization and a generalized…

Abstract

The finite element quasi‐static analysis of elastoplastic systems is studied by making use of a generalized variable approach for the spatial discretization and a generalized mid‐point rule for the time integration. Both the classical form of the constitutive law and the convex analysis formulation are presented. The relation between the mid‐point time integration and the extremal path theory is discussed. Extremal properties for the finite‐step solution are formulated.

Details

Engineering Computations, vol. 11 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 March 1988

B. Kröplin and D. Dinkler

The load carrying capacity of steel structures, built of slender members like bridge cross‐sections, depends on coupled yielding and buckling of the stringers and the plate strips…

Abstract

The load carrying capacity of steel structures, built of slender members like bridge cross‐sections, depends on coupled yielding and buckling of the stringers and the plate strips as well as on the global buckling. Therefore, the common techniques of modelling the limit load by an elasto‐plastic layer model fail. In order to overcome the difficulty a material law is developed, in which local buckling failure and yielding is considered. This is based on an energy function, which describes the elasto‐plastic intermediate and ultimate state of plates and webs dependent on only a few parameters. The application is shown on large scale examples of stiffened steel bridge decks.

Details

Engineering Computations, vol. 5 no. 3
Type: Research Article
ISSN: 0264-4401

Article
Publication date: 1 December 2004

George K. Stylios

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects…

3517

Abstract

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

Details

International Journal of Clothing Science and Technology, vol. 16 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 16 October 2017

Chunxia Zhu, Jay Katupitiya and Jing Wang

Manipulator motion accuracy is a fundamental requirement for precision manufacturing equipment. Light weight manipulators in high speed motions are vulnerable to deformations. The…

Abstract

Purpose

Manipulator motion accuracy is a fundamental requirement for precision manufacturing equipment. Light weight manipulators in high speed motions are vulnerable to deformations. The purpose of this work is to analyze the effect of link deformation on the motion precision of parallel manipulators.

Design/methodology/approach

The flexible dynamics model of the links is first established by applying the Euler–Bernoulli beam theory and the assumed modal method. The rigid-flexible coupling equations of the parallel mechanism are further derived by using the Lagrange multiplier approach. The elastic energy resulting from spiral motion and link deformations are computed and analyzed. Motion errors of the 3-link torque-prismatic-torque parallel manipulator are then evaluated based on its inverse kinematics. The validation experiments are also conducted to verify the numerical results.

Findings

The lateral deformation and axial deformation are largest at the middle of the driven links. The axial deformation at the middle of the driven link is approximately one-tenth of the transversal deformation. However, the elastic potential energy of the transversal deformation is much smaller than the elastic force generated from axial deformation.

Practical implications

Knowledge on the relationship between link deformation and motion precision is useful in the design of parallel manipulators for high performing dynamic responses.

Originality/value

This work establishes the relationship between motion precision and the amount of link deformation in parallel manipulators.

Details

Industrial Robot: An International Journal, vol. 44 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 10 March 2022

Yangyang Dong, Tongle Zhang, Shaojie Han, Yipan Guo, Bo Zeng, Yongbin Wang and Zijian Zhang

Spherical robot plays an essential role in the field of mobile robot because of its unique shape and omni-directional mobility, especially in the application of planet detection…

Abstract

Purpose

Spherical robot plays an essential role in the field of mobile robot because of its unique shape and omni-directional mobility, especially in the application of planet detection. Although spherical robot has many advantages over leg robot, its obstacle climbing performance is still not satisfactory, that is exactly the motivation of this paper. The purpose of this paper is to propose a high-performance hopping mechanism for spherical robot, which can adapt to different terrain and effectively cross obstacles.

Design/methodology/approach

The hopping system uses torque spring as part of the energy storage mechanism, and converts the kinetic energy of rotation into elastic potential energy with a particularly designed turntable. Moreover, the track of the turntable, based on the Archimedes spiral principle, has the attributes of equidistance and equivelocity that enable better stability of energy storage process.

Findings

Experiments show that the proposed hopping mechanism can make a 250 g spherical robot jump up to 58 cm with the take-off angle of 60°. Finally, the influence of friction and take-off angle on the hopping height and distance of the robot is also analyzed, which provides a prior guidance for optimizing its jumping process.

Originality/value

This paper shows how to easily design a lightweight, compact and embedded spring hopping structure so that a spherical hopping robot with detection ability can be developed.

Details

Industrial Robot: the international journal of robotics research and application, vol. 49 no. 4
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 29 June 2023

Yingli Li, Chenwei Wu, Yong Peng and Xudong Jiang

In order to investigate the vibration reduction properties of a three-dimensional elastic metastructure with spherical cavities at low frequencies.

Abstract

Purpose

In order to investigate the vibration reduction properties of a three-dimensional elastic metastructure with spherical cavities at low frequencies.

Design/methodology/approach

The bandgap characteristics of a three-dimensional elastic metastructure with spherical cavities are studied based on analytical and numerical approaches.

Findings

The results of both method revealed that the vibration of the vertexes masses is important for opening bandgaps. The fact that the big sphere cavity radius or short side length of the cube unit leads to a wider bandgap, is noteworthy.

Originality/value

This research provides theoretical guidance for realizing the vibration attenuation application of EMs in practical engineering.

Details

International Journal of Structural Integrity, vol. 14 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 17 April 2020

Adrian Pavel Pugna, Sabina Alina Potra and Romeo Negrea

The present study aims to further research the theory of attractive quality for new offers by analyzing the HWWP (Health, Weapon, Wealth, Prospect) model and testing its…

420

Abstract

Purpose

The present study aims to further research the theory of attractive quality for new offers by analyzing the HWWP (Health, Weapon, Wealth, Prospect) model and testing its uniformity. The purpose is to extend and refine the HWWP model based on meridian elasticity curves with the final scope of building a map for better understanding the potential value of the quality attributes in new product or strategic service design.

Design/methodology/approach

After a thorough analysis of the HWWP model for prepurchase value judgment, it has been observed that the classical form often presents a concentration of the quality attributes in its graphic representation, which limits managerial decision making. This paper presents a new methodology for testing the uniformity of the current HWWP model and a generalized approach for understanding the potential lifecycle of the new offer's features.

Findings

The results of the presented case study validate the novel tool’s applicability and can serve as a reference for managers to adequately classify customer requirements as the first step toward strategic design.

Originality/value

The author’s main contributions are: to have analyzed the current HWWP model and observed the limitations of this approach; to have proposed a statistical simple method used to test the uniformity of the HWWP model; to have developed a generalized new HWWP model that adequately explores each feature value and potential lifecycle base on meridian slices and elasticity orbits.

Article
Publication date: 1 June 1988

Terence W. Bates, Brian Williamson, James A. Spearot and Chester K. Murphy

Oil film thickness measurements made in the front main bearing of an operating 3.8 L, V‐6 engine were compared with rheological measurements made on a series of commercial and…

Abstract

Oil film thickness measurements made in the front main bearing of an operating 3.8 L, V‐6 engine were compared with rheological measurements made on a series of commercial and experimental oil blends. High‐temperature, high‐shear‐rate viscosity measurements correlated with the film thickness of all single‐grade and many multigrade oils. However, the film thickness provided by some multigrade oils were larger than could be accounted for by their high‐temperature, high‐shear‐rate viscosities alone. Although the pressure/viscosity coefficients of some of the oils were significantly different from those of the majority of oils tested, they were not oils which produced unusual film thicknesses. As a consequence, correcting oil viscosities for the esimated pressures acting within the bearing was unsuccessful in improving the correlations. The correlations were improved, however, by accounting for the elastic properties of the multigrade oils. Measurements of oil relaxation times at high temperatures and shear rates showed large differences in elastic properties among the test oils. A good correlation (R2 = 0.73) was obtained from a multiple linear regression of film thickness as a function of both high‐temperature, high‐shear‐rate viscosities and relaxation times.

Details

Industrial Lubrication and Tribology, vol. 40 no. 6
Type: Research Article
ISSN: 0036-8792

Article
Publication date: 9 August 2011

Mondher Wali, Moez Abdennadher, Tahar Fakhfakh and Mohamed Haddar

The purpose of this paper is to analyse the dynamic behaviour of an elasto‐plastic sandwich subjected to low velocity impact.

Abstract

Purpose

The purpose of this paper is to analyse the dynamic behaviour of an elasto‐plastic sandwich subjected to low velocity impact.

Design/methodology/approach

A numerical model is developed with the assumption that the plastic deformation is confined under the contact area. The structure is analyzed using the in‐house finite element code with an appropriate contact law. During the impact progression, two phases (elastic and plastic) related to the impact intensity are considered in the dynamic model. The proportional viscous damping is incorporated in the model. An elasto‐plastic impact algorithm is established to determine the impact force, the sandwich structure displacement and indentation.

Findings

The numerical results are validated by experimental dropping weight impact tests. The influences of the impactor radius, the core material variation and the impactor initial velocity on the dynamic behaviour of the impacted structure are studied.

Originality/value

In order to study the low velocity impact problems by considering the caused plastic deformations, a simple numerical elasto‐plastic impact model of sandwich structure is proposed.

Details

Multidiscipline Modeling in Materials and Structures, vol. 7 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 25 March 2021

Yudong Zhang, Leiying He and Chuanyu Wu

The purpose of this paper is to study the preload range of tendon-driven manipulator and the relationship between preload and damping. The flexible joint manipulator (FJM) with…

Abstract

Purpose

The purpose of this paper is to study the preload range of tendon-driven manipulator and the relationship between preload and damping. The flexible joint manipulator (FJM) with joint flexibility is safer than traditional rigid manipulators. A FJM having an elastic tendon is called an elastic tendon-driven manipulator (ETDM) and has the advantages of being driven by a cable and having a more flexible joint. However, the elastic tendon introduces greater residual vibration, which makes the control of the manipulator more difficult. Accurate dynamic modeling is effective in solving this problem.

Design/methodology/approach

The present paper derives the relationship between the preload of the ETDM and the friction moment through the analysis of the forces of cables and pulleys. A dynamic model dominated by Coulomb damping is established.

Findings

The linear relationship between a decrease in the damping moment of the system and an increase in the ETDM preload is verified by mechanics analysis and experiment, and a curve of the relationship is obtained. This study provides a reference for the selection of ETDM preload.

Originality/value

The method to identify ETDM damping by vibration attenuation experiments is proposed, which is helpful to obtain a more accurate dynamic model of the system and to achieve accurate control and residual vibration suppression of ETDM.

Details

Industrial Robot: the international journal of robotics research and application, vol. 48 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

21 – 30 of over 5000