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Article
Publication date: 2 November 2018

Jinwu Xiang, Kai Liu, Daochun Li, Chunxiao Cheng and Enlai Sha

The purpose of this paper is to investigate the unsteady aerodynamic characteristics in the deflection process of a morphing wing with flexible trailing edge, which is…

415

Abstract

Purpose

The purpose of this paper is to investigate the unsteady aerodynamic characteristics in the deflection process of a morphing wing with flexible trailing edge, which is based on time-accurate solutions. The dynamic effect of deflection process on the aerodynamics of morphing wing was studied.

Design/methodology/approach

The computational fluid dynamic method and dynamic mesh combined with user-defined functions were used to simulate the continuous morphing of the flexible trailing edge. The steady aerodynamic characteristics of the morphing deflection and the conventional deflection were studied first. Then, the unsteady aerodynamic characteristics of the morphing wing were investigated as the trailing edge deflects at different rates.

Findings

The numerical results show that the transient lift coefficient in the deflection process is higher than that of the static case one in large angle of attack. The larger the deflection frequency is, the higher the transient lift coefficient will become. However, the situations are contrary in a small angle of attack. The periodic morphing of the trailing edge with small amplitude and high frequency can increase the lift coefficient after the stall angle.

Practical implications

The investigation can afford accurate aerodynamic information for the design of aircraft with the morphing wing technology, which has significant advantages in aerodynamic efficiency and control performance.

Originality/value

The dynamic effects of the deflection process of the morphing trailing edge on aerodynamics were studied. Furthermore, time-accurate solutions can fully explore the unsteady aerodynamics and pressure distribution of the morphing wing.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 1
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 1 August 2011

M. Ghane, T. Ghahraman, M. Sheikhzadeh and A.M. Halabian

A fabric can be modeled as an elastic beam supported by simple supports subjected to its own weight. The maximum deflection in the middle can be measured accurately…

Abstract

A fabric can be modeled as an elastic beam supported by simple supports subjected to its own weight. The maximum deflection in the middle can be measured accurately. Different types of fabrics are tested and the bending modulus of the fabrics is then calculated in both small and large deflection cases. In the case of large deflection, the finite element method is used to solve the governing differential equation. The difference between the values of the bending modulus obtained from the small and large deflection cases increases as the length of the bent fabric is increased. The reason is less accuracy of the small deflection equations in longer lengths of the beam. However, the results reveal that even in the longest length of the tested beam (fabric), the differences between the values of the bending modulus from small and large deflection cases are in an acceptable range. It can be concluded that the case of the small deflection can be used to calculate the bending modulus of the fabrics in a simply supported beam method with an acceptable accuracy.

Details

Research Journal of Textile and Apparel, vol. 15 no. 3
Type: Research Article
ISSN: 1560-6074

Keywords

Article
Publication date: 15 September 2020

Shiwei Zhao, Daochun Li and Jinwu Xiang

The purpose of this study is to propose an improved design of PneuNets bending actuator which aims at obtaining larger deflection with the same magnitude of pressure. The…

Abstract

Purpose

The purpose of this study is to propose an improved design of PneuNets bending actuator which aims at obtaining larger deflection with the same magnitude of pressure. The PneuNets bending actuator shows potential application in the morphing trailing edge concept.

Design/methodology/approach

Finite element method is used to investigate the characteristics of the improved design bending actuator. Multiobjective optimal design of the PneuNets bending actuator is proposed based on the Gauss process regression models.

Findings

The maximum deflection is obtained when the height of the beams is smaller than half the height of the chambers. The spacing between chambers (beam length) has little effect on the deflection. Larger spacing could be used to reduce the actuator weight.

Originality/value

With the same pressure magnitude, the deflection of the improved design bending actuator is much larger than that of the baseline configuration. PneuNets bending actuator could increase the continuity of the aerodynamic surface compared to other actuators.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 10
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 14 September 2010

Bian Tian, Yulong Zhao and Zhuangde Jiang

The purpose of this paper is to investigate the disadvantages of traditional sensors and establish a new structure for pressure measurement.

1247

Abstract

Purpose

The purpose of this paper is to investigate the disadvantages of traditional sensors and establish a new structure for pressure measurement.

Design/methodology/approach

A kind of novel piezoresistive micro‐pressure sensor with a cross‐beam membrane (CBM) structure is designed based on the silicon substrate. Through analyzing the stress distribution of the new structure by finite element method, the model of structure is established and compared with traditional structures. The fabrication is operated on silicon wafer, which applies the technology of anisotropy chemical etching and inductively coupled plasma.

Findings

Compared to the traditional C‐ and E‐type structures, this new CBM structure has the advantages of low nonlinearity and high sensitivities by the cross‐beam on the membrane, which cause the stress is more concentrated in sensitive area and the deflections that relate to the linearity are decreased.

Originality/value

The paper provides the first empirical reports on the new piezoresistive structure for the pressure measurement by fabricating a cross‐beam on the membrane and resolving the conflict of nonlinearity and sensitivity of the piezoresistive sensors.

Details

Sensor Review, vol. 30 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 12 December 2016

Serdar Selamet and Caner Bolukbas

This paper aims to present a numerical investigation on the fire performance of a single plate shear connection in a steel-framed composite floor. Large-scale fire…

Abstract

Purpose

This paper aims to present a numerical investigation on the fire performance of a single plate shear connection in a steel-framed composite floor. Large-scale fire experiments show that the tensile membrane action of the concrete slab enhances the fire performance of composite floors. The enhancement in the performance is contributed to large slab deflections. However, these deflections cause significant rotations and tensile force in the single plate connection.

Design/methodology/approach

A finite element model is constructed, which consists of a secondary steel beam, concrete slab and shear connection components. The interaction between the connection components such as bolts and single plate is defined by contact surfaces. The analysis is conducted in two uncoupled phases: thermal analysis by creating fire boundaries on the composite floor model with convective and radiative heat transfer, and mechanical analysis by considering thermal expansion and changes in the material stiffness and strength due to temperature.

Findings

The thermo-mechanical analysis of the composite floor finite element model shows that the structure survives the 2-h Standard fire, but the connection fails by bolt shear and buckling of the connection plate.

Originality/value

This paper investigates the fire performance of a shear connection in a steel-framed concrete slab. Previous work generally focused on the concrete slab behavior only. The originality of the research is that the connection is considered as part of a sub-assembly and is subjected to forces due to concrete and steel beam interaction.

Details

Journal of Structural Fire Engineering, vol. 7 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 14 December 2021

Fuminobu Ozaki and Takumi Umemura

In this study, the bending strength, flexural buckling strength and collapse temperature of small steel specimens with rectangular cross-sections were examined by steady…

Abstract

Purpose

In this study, the bending strength, flexural buckling strength and collapse temperature of small steel specimens with rectangular cross-sections were examined by steady and transient state tests with various heating and deformation rates.

Design/methodology/approach

The engineering stress and strain relationships for Japan industrial standard (JIS) SN400 B mild steels at elevated temperatures were obtained by coupon tests under three strain rates. A bending test using a simple supported small beam specimen was conducted to examine the effects of the deformation rates on the centre deflection under steady-state conditions and the heating rates under transient state conditions. Flexural buckling tests using the same cross-section specimen as that used in the bending test were conducted under steady-state and transient-state conditions.

Findings

It was clarified that the bending strength and collapse temperature are evaluated by the full plastic moment using the effective strength when the strain is equal to 0.01 or 0.02 under fast strain rates (0.03 and 0.07 min–1). In contrast, the flexural buckling strength and collapse temperature are approximately evaluated by the buckling strength using the 0.002 offset yield strength under a slow strain rate (0.003 min–1).

Originality/value

Regarding both bending and flexural buckling strengths and collapse temperatures of steel members subjected to fire, the relationships among effects of steel strain rate for coupon test results, heating and deformation rates for the heated steel members were minutely investigated by the steady and transient-state tests at elevated temperatures.

Article
Publication date: 27 April 2010

John T. Montgomery, Meagan R. Vaughan and Richard H. Crawford

A prosthetic socket worn by an amputee must serve a wide variety of functions, from stationary support to the transfer of forces necessary to move. Because a subject's…

1160

Abstract

Purpose

A prosthetic socket worn by an amputee must serve a wide variety of functions, from stationary support to the transfer of forces necessary to move. Because a subject's residual limb changes volume throughout the day, it is desirable that the socket adapt to accommodate volume changes to maintain fit and comfort. The purpose of this paper is to provide steps towards designing a transtibial nylon prothestic socket, fabricated by selective laser sintering (SLS), that automatically adapts to volumetric changes of a residual limb.

Design/methodology/approach

An adaptive socket design that has both rigid and compliant regions is proposed to be manufactured by SLS and actuated by inflation. To assess the feasibility of this approach, thin membrane test specimens of various thicknesses and materials were created to understand the relationship between inflation pressure and deflection for SLS manufactured plastics. Finite element analysis (FEA) was assessed as a predictive design tool and verified with the experimental inflation/deflection results.

Findings

The initial flat test specimens could only achieve deflection of 2.13 mm at 145 kPa (nylon 12) and 3.38 mm at 340 kPa (nylon 11). A curved specimen is created that met performance goals with 7.67 mm maximum deflection at 714 kPa. FEA for the flat specimens is an accurate predictor of performance, but the results of analyzing the curved specimens are an order of magnitude different from the experimental data.

Research limitations/implications

The success of the physical curved specimens is encouraging for future research, but the FEA will need to be further developed before socket performance can be predicted with confidence.

Originality/value

A socket that does not fit the subject well will cause movement problems, rehabilitation difficulties, and potentially long‐term health issues. This research shows great potential for developing a socket that provides greater comfort and fit.

Details

Rapid Prototyping Journal, vol. 16 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 20 August 2021

Pandimani, Markandeya Raju Ponnada and Yesuratnam Geddada

This paper aims to present nonlinear numerical simulations using the versatile finite element (FE) analysis tool ANSYS and theoretical analysis based on code provisions to…

Abstract

Purpose

This paper aims to present nonlinear numerical simulations using the versatile finite element (FE) analysis tool ANSYS and theoretical analysis based on code provisions to assess the load-carrying capacity of reinforced concrete (RC) beams under two-point monotonic static loadings.

Design/methodology/approach

Four quarter-size FE models with load and geometry symmetry conditions were constructed, the load-bearing capacity and associated mid-span deflections at critical points are verified against the full-scale experimental RC beams available in the literature. These developed FE models incorporated the tension stiffening effects and bond–slip behaviour. Theoretical analyses based on Indian standard code IS: 456–2000 and ACI 318–19 were also carried to verify the experimental and numerical predicted moments at critical loading points.

Findings

The load-deflection curves predicted through FE models exhibit closer corroboration with the experimental curves throughout the loading history. The contour plots for deflections, concrete principal stresses, reinforcement yield stresses are satisfactorily predicted by the FE models, which reveal the complete information of nonlinear behaviour of RC beams. The developed model well captured the initial and progressive crack patterns at each load increments.

Practical implications

The FE modelling is an efficient, valid and economical tool that is an alternative to the expensive experimental program and can be used to explore, analyse and fully understand the nonlinear response of RC beams under static loadings.

Originality/value

The ultimate moment capacity evaluated based on ACI 318–19 code provision show a better correlation with the experimental data as compared to the IS: 456–2000 code provision. The ultimate loads and associated centre-span deflections predicted by RN-2, RN-3, RB-12 and RB-16 FE model show a discrepancy of 1.66 and –0.49%, –4.68 and –0.60%, –9.38 and –14.53% and –4.37 and 4.21%, respectively, against the experimental results, which reveals that the developed ANSYS FE models predict consistent results and achieved a reasonable agreement with the experimental data.

Details

Journal of Engineering, Design and Technology , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1726-0531

Keywords

Article
Publication date: 7 August 2007

Uma Maheshwaraa, David Bourell and Carolyn Conner Seepersad

Frontier environments – such as battlefields, hostile territories, remote locations, or outer space – drive the need for lightweight, deployable structures that can be…

3017

Abstract

Purpose

Frontier environments – such as battlefields, hostile territories, remote locations, or outer space – drive the need for lightweight, deployable structures that can be stored in a compact configuration and deployed quickly and easily in the field. This paper seeks to introduce the concept of lattice skins is introduced to enable the design, solid freeform fabrication (SFF), and deployment of customizable structures with nearly arbitrary surface profile and lightweight multi‐functionality.

Design/methodology/approach

Using Duraform® FLEX material in a selective laser sintering machine, large deployable structures are fabricated in a nominal build chamber by decomposing them into smaller parts. Before fabrication, lattice sub‐skins are added strategically beneath the surface of the part. The lattices provide elastic energy for folding and deploying the structure or constrain expansion upon application of internal air pressure. Nearly, arbitrary surface profiles are achievable and internal space is preserved for subsequent usage.

Findings

A set of virtual and physical prototypes are presented, along with the computational modeling approach used to design them. The prototypes provide proof of concept for lattice skins as a deployment mechanism in SFF and demonstrate the effect of lattice structures on deployed shape.

Research limitations/implications

The research findings demonstrate not only the feasibility of a new deployment mechanism‐based on lattice skins – for deploying freeform structures, but also the potential utility of SFF techniques for fabricating customized deployable structures.

Originality/value

A new lattice skin mechanism is introduced for deploying structures with nearly arbitrary surface profiles and open, usable, internal space. Virtual and physical prototypes are introduced for proof of concept, along with an optimization approach for automated design of these structures.

Details

Rapid Prototyping Journal, vol. 13 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 April 1985

H.R. Evans, D.O. Peksa and A.R. Taherian

The paper reviews the application of the finite element method to the analysis of largedeflection elasto‐plastic behaviour and traces the development of such a solution…

Abstract

The paper reviews the application of the finite element method to the analysis of largedeflection elasto‐plastic behaviour and traces the development of such a solution for plated structures. The accuracy of the approach is established by many comparisons with available solutions for isolated plates and conclusions are drawn on suitable idealizations for plated structures. The results of an analysis of a typical plate girder, allowing fully for the interaction between the component plates, are presented. Comparisons with experimentally measured values for the girder confirm the validity of the proposed approach for the study of the collapse modes of plated structures. The need for expensive experimentation is thereby reduced.

Details

Engineering Computations, vol. 2 no. 4
Type: Research Article
ISSN: 0264-4401

1 – 10 of over 3000