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Post-Buckling Behavior of Laminated Composite Cylindrical Shells Subjected to Axial, bending and Torsion Loads

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World Journal of Engineering and Technology 2015年第4期3卷 185-194页

作者： Yengula Venkata Narayana Jagadish Babu Gunda Ravinder Reddy Pinninti Markandeya Ravvala Department of Mechanical Engineering Sreenidhi Institute of Science and Technology Hyderabad India Advanced Systems Laboratory Kanchan Bagh Hyderabad India Department of Mechanical Engineering Chaitanya Bharathi Institute of Science and Technology Hyderabad India Department of Metallurgical Engineering JNTUH Hyderabad India

In present work, post-buckling behavior of imperfect (of eigen form) laminated composite cylindrical shells with different L/D and R/t ratios subjected to axial, bending and torsion loads has been investigated by using an equilibrium path approach in the finite element analysis. The Newton-Raphson approach as well as the arc-length approach is used to ensure the correctness of the equilibrium paths up to the limit point load. Post-buckling behavior of imperfect cylindrical shells with different L/D and R/t ratios of interest is obtained and the theoretical knock-down factors are reported for the considered cylindrical shells.

关键词： Post-Buckling Cylindrical Shells Eigen Imperfection Shapes Axial Compressive Load bending Load Torsion Load Arc-Length Method Knock-Down Factor

Evaluation of the bending Loss of the Hollow Optical Fiber for Application of the Carbon Dioxide Laser to Endoscopic Therapy

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Optics and Photonics Journal 2013年第4期3卷 14-19页

作者： Daisuke Kusakari Hisanao Hazama Rinna Kawaguchi Katsunori Ishii Kunio Awazu 1Graduate School of Engineering Osaka University Osaka Japan 2Graduate School of Frontier Biosciences Osaka University Osaka Japan 3The Center for Advanced Medical Engineering and Informatics Osaka University Osaka Japan Graduate School of Engineering Osaka University Osaka Japan

Since carbon dioxide laser is excellent for incision, hemostasis, coagulation, and vaporization of soft tissues, it has been widely applied in clinical treatments as the laser knife. In these days, flexible thin hollow optical fibers transmitting mid-infrared light have been developed, and the application of carbon dioxide laser to endoscopic therapy has become possible. However, it is expected that the irradiation effect is influenced by the change in the laser power at the tip of the hollow optical fiber due to the change in the transmittance by the bending loss. The purpose of this research is to quantitatively evaluate the change in the output power and therapeutic effect by bending the hollow optical fiber in a gastrointestinal endoscope. The change in the transmittance of the hollow optical fiber due to the insertion of the fiber into the endoscope and bending of the head of the endoscope was measured. Then, the relationship between the irradiated laser power and the incision depth for a porcine stomach was investigated. As the results, the most significant decrease in the transmittance of the hollow optical fiber was caused by the insertion of the fiber into the instrument channel of the endoscope, and bending of the head of the endoscope with the angle of 90° decreased the output laser power and incision depth by 10% and 25%, respectively. Therefore, it was confirmed that the bending loss of the hollow optical fiber due to the bending of the head of the endoscope had no significant influence on the endoscopic therapy using the carbon dioxide laser.

关键词： Hollow Optical Fiber Carbon Dioxide Laser bending Loss Endoscopic Therapy

A Comparison of bending Properties for Cellular Core Sandwich Panels

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Materials Sciences and Applications 2013年第8期4卷 471-477页

作者： Li Yang Ola Harrysson Harvey West Denis Cormier Department of Industrial & Systems Engineering North Carolina State University Raleigh USA Department of Industrial & Systems Engineering Rochester Institute of Technology Rochester USA Department of Industrial Engineering University of Louisville Louisville USA

In this study, various sandwich panel structures with different reticulate lattice core geometries were designed and then fabricated in titanium via the electron beam melting (EBM) process. bending tests were performed on the titanium samples, and mechanical properties such as modulus, bending strength, and energy absorption were evaluated. Different failure mechanisms were observed, and it was found that sandwich structures with auxetic cores exhibited more homogeneous deflection and bending compliance compared with other structures. It was also demonstrated that properties of auxetic sandwich structures can be tailored using different cell structure geometries to suit the needs of a given design application. Furthermore, it was found that other 3D cellular sandwich structures can also exhibit high stiffness and strength, which is desirable in potential applications.

关键词： Auxetic Structure Cellular Structure Sandwich Panels Electron Beam Melting bending Properties

A Comparative Study of Stress Recovery Method and Error Estimation of Plate bending Problem Using DKMQ Element

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Modern Mechanical Engineering 2012年第2期2卷 47-55页

作者： Irwan Katili Aziz Hamdouni Olivier Millet J. I. Rastandi Imam J. Maknun LEPTIAB Université de La Rochelle La Rochelle France Universitas Indonesia Depok Indonesia

Recovery by Equilibrium in Patches (REP) is a recovery method introduced by B. Boroomand. This method is using patch as recovery media as is used by Superconvergent Patch Recovery (SPR) which is well known as a good recovery method. In this research, a numerical study of REP implementation is held to estimate error in finite element analysis using DKMQ element. The numerical study is performed with both uniform and adaptive h-type mesh refinement. The result is compared with three other recovery method, i.e. SPR method, averaging method, and projection method.

关键词： bending Plate Finite Element Method Superconvergent Patch Recovery Recovery by Equilibrium in Patches DKMQ Element

Assessment of Existing Bridge’s Beam bending Stiffness Using Crack Characteristics

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Engineering（科研） 2020年第2期12卷 82-89页

作者： Donglian Tan Shanghai Institute of Technology Shanghai China

At present, the bearing capacity evaluation is mainly based on load detection, which requires closed traffic and has certain risks. With the increase of service time, the cracks of reinforced concrete beam bridge will gradually develop and the stiffness will reduce, resulting in the decrease of bearing capacity. Therefore, in this paper, the calculation of stiffness reduction coefficient by using crack characteristic parameters, which provides basic data for bearing capacity evaluation, has been studied. In this paper, using regression analysis through fracture characteristics of four model beam observation and test load-displacement curve characteristic parameters, crack flexural rigidity of the beam bridge relationship has been set up. The qualitative assessment based appearance of cracks in the structure of checks has been converted to quantitative assessment. And compared with the test results of a real bridge, comparative results show that the assessment is objective and reliable. It makes the assessment more objective and scientific. A new way of Quantitative assessment of the structural performance has been provided for a large number of existing reinforced concrete beam bridge.

关键词： Beam Bridge Crack Characteristics bending Stiffness Assessment

Nonlinear bending of Piezoelectric Cylindrical Shell Reinforced with BNNTs under Electro-Thermo-Mechanical Loadings

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Materials Sciences and Applications 2015年第8期6卷 743-752页

作者： Jinhua Yang Pengjun Zhang School of Civil Engineering and Architecture Changsha University of Science & Technology Changsha China

Under combined electro-thermo-mechanical loadings, the nonlinear bending of piezoelectric cylindrical shell reinforced with boron nitride nanotubes (BNNTs) is investigated in this paper. By employing nonlinear strains based on Donnell shell theory and utilizing piezoelectric theory including thermal effects, the constitutive relations of the piezoelectric shell reinforced with BNNTs are established. Then the governing equations of the structure are derived through variational principle and resolved by applying the finite difference method. In numerical examples, the effects of geometric nonlinear, voltage, temperature, as well as volume fraction on the deflection and bending moment of axisymmetrical piezoelectric cylindrical shell reinforced with BNNTs are discussed in detail.

关键词： Nonlinear bending Piezoelectric Cylindrical Shell BNNT Electro-Thermo-Mechanical Loadings

Optimization of Energy Density in Girders under Pure bending with an Extruded Monolithic Cross-Section

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World Journal of Mechanics 2019年第3期9卷 53-66页

作者： Daniel Fernández Caballero Víctor Rodríguez de la Cruz Juan Manuel Munoz Guijosa Department of Mechanical Engineering Universidad Pontificia ICAI Madrid Spain Department of Mechanical Engineering Escuela Técnica Superior de Ingenieros Industriales Universidad Politécnica de Madrid Madrid Spain

This article proposes use of extruded compound materials with optimized resistant cross-sections as an alternative, in this case, seeking the maximum energy density as a design criterion. The advantage of this proposa... 详细信息

关键词： Pure bending Energy Storage Composite Material Extruded Cross-Section Design Optimization

Thermal bending of Circular Plates for Non-Axisymmetrical Problems

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World Journal of Mechanics 2011年第2期1卷 44-49页

作者： Zhengzhu Dong Weihong Peng Jun Li Fashan Li 不详

Using the Green function, the boundary integral formula and natural boundary integral equation for thermal elastic problems are obtained. Then based on bending solutions to circular plates subjected to the non-axi- symmetrical load, by utilizing the Fourier series and convolution formulae, the bending solutions under non-axisymmetrical thermal conditions have been obtained. The calculating process is simple. Examples show the discussed methods are effective.

关键词： Thermal bending Problems Circular Plate Boundary Integral Formula Natural Boundary Integral Equation

Foreleg bending in Blue Foxes (<i>Vulpes lagopus</i>) as Evaluated by Radiography

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Open Journal of Veterinary Medicine 2015年第3期5卷 61-67页

作者： Hannu T. Korhonen Pekka Eskeli Hanna Huuki Juhani Sepponen Natural Resources Institute Finland (Luke) Kannus Finland

The aim was to compare radiographic X-ray data to foreleg bending, moving difficulties and body size in juvenile blue foxes. Experimental groups were: 1) restricted feeding, Ca:P ratio 1.5:1 (R 1);2) restricted feeding, Ca:P ratio 2.9:1 (R 2);3) restricted feeding Ca:P ratio 2.0:1 control level (R 3);4) ad libitum feeding, Ca:P ratio 1.5:1 (AL 1);5) ad libitum feeding, Ca:P ratio 2.9:1 (AL 2);6) ad libitum feeding Ca:P ratio 2.0:1 control level (AL 3). Moving difficulties and foreleg bending were evaluated in live animals. At pelting, left foreleg was removed. X-ray pictures were taken from lateral views. Dimensions of ulna and radius were measured from the X-ray pictures. Conditions of carpal joint and elbow joint were visually evaluated. The results showed that final body weight was affected by feeding intensity (P = 0.001). Ad libitum fed animals had more moving difficulties compared to restricted ones (P = 0.001). The Ca:P ratio tended (P = 0.06) to have an effect on feet bending. bending was greatest in low Ca:P ratio (1.5:1) and, correspondingly, least in high Ca:P ratio (2.9:1). Moving difficulties were most common in heaviest animals. The moving difficulties tended (P = 0.07) to be positively related to feet bending. Maximum width of ulna was lowest in low Ca:P ratio diet (1.5:1). bending was negatively correlated with maximum width of ulna. It can be concluded that low Ca:P ratio in the diet (1.5:1) increases foreleg bending in juveniles. Moving difficulties are related to foreleg bending and high body weight.

关键词： Vulpes lagopus Foot Welfare Moving Difficulties Feet bending Blue Fox