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Finite Element Modelling of Steel Beams with Web Openings  [PDF]
Flavio Rodrigues, Pedro C. G. da S. Vellasco, Luciano R. O. de Lima, Sebastião A. L. de Andrade
Engineering (ENG) , 2014, DOI: 10.4236/eng.2014.613082
Abstract: Height limitations are not uncommon in multi-storey buildings due to economic requirements and esthetical considerations. Substantial spaces are normally required to enable the passage of large pipes and ducts beneath steel beams leading to uneconomic floor heights. The most adopted solution for this issue is the use of steel beam web openings to provide the required space for services. These openings could lead to a significant decrease of the beam load carrying capacity depending on the adopted openings shape, size and location. These aspects motivated the present study based on FE simulations calibrated against numerical and test results. The results accuracy enabled a comprehensive parametric analysis of beams with web openings to be made focused on the profile size, web opening location, among others. The study also investigated the efficiency of longitudinal stiffeners welded at the opening region and benefits of using an adequate edge concordance radius in beams with rectangular and square openings. The obtained results showed the need of using welded longitudinal stiffeners in order to increase the beams ultimate load carrying capacity. This adoption can double or even triple the ultimate load of beams with rectangular and square opening heights equal to 0.75 H, respectively.
Strengthening of RC Beams with Large Openings in Shear by CFRP Laminates: Experiment and 2D Nonlinear Finite Element Analysis  [cached]
S.C. Chin,N. Shafiq,M.F. Nuruddin
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: This study presents the experimental study and numerical analysis of Reinforced Concrete (RC) beams with large square openings placed in the shear region, at a distance 0.5d and d away from the support, strengthened by Carbon Fiber Reinforced Polymer (CFRP) laminates. This research aims to investigate the strength losses in RC beam due to the presence of large square openings placed at two different locations in shear region. Also, in order to re-gain the beam structural capacity loss due to the openings, strengthening by CFRP laminates around the openings were studied. A total of six RC beams were tested to failure under four point loading including control beams, un-strengthened and strengthened RC beams with large square openings in shear region at a distance 0.5d and d away from the support. The CFRP strengthening configuration considered in this study was a full wrapping system around the square openings. A nonlinear finite element program, ATENA was used to validate the results of the tested beams. Comparisons between the finite element predictions and experimental results in terms of crack patterns and load deflection relationships are presented. The crack pattern results of the finite element model show good agreement with the experimental data. The load midspan deflection curves of the finite element models exhibited a stiffer result compared to the experimental beams. The possible reason may be due to the perfect bond assumption between the concrete and steel reinforcement.
Strengthening of steel beam around rectangular web openings
B.Durga Prakash,,L.M.Gupta,,P.D.Pachpor,,N.V.Deshpande
International Journal of Engineering Science and Technology , 2011,
Abstract: Modern multistory buildings always have a stringent requirement on headroom, in order to accommodate buildings services within the constructional depth of floor; it is common practice to provide web openings in structural floor beams for passage of services. The structural behavior of steel beams with web openings, and also for composite beams with single rectangular web openings, both with or without reinforcement is studied. Rectangular web openings are often formed with various aspect ratios, while the web openings depth isrestricted to 50% of the overall section height. Though several design procedures have been developed for structural beam with web openings, to date the behavior of steel beams with web openings is not known due to the large no: of parameters involved and the complexity involved in analyzing the steel beams with web openings. In this paper Finite Element Analysis is used to analyze the steel beams. The stress values & the deflections are observed. The results have been plotted for stress values and the deflections, with respect to the change in span ratio.
Finite Element Approach of Shielded, Suspended and Inverted Microstrip Lines  [cached]
Sarhan Musa,Matthew N.O. Sadiku
Buletin Teknik Elektro dan Informatika , 2013,
Abstract: In this paper, we present finite element method (FEM) to investigate the electromagnetic analysis of two-dimensional (2D) shielded, suspended and inverted microstrip lines for microwave applications. In the proposed method, we specifically determine the values of capacitance per unit length, inductance per unit length, and characteristic impedance of the microstrip lines. Extensive simulation results are presented and some comparative results are given with other methods and found them to be in excellent agreement. We extend the analysis by designing our new model of shielded, inverted microstrip lines and compared it with shielded, suspended microstrip lines; we found them to be very close. Also, we determine the quasi-TEM spectral for the potential distribution of these microstrip lines.
Santanu Mondal
International Journal of Soft Computing & Engineering , 2012,
Abstract: The proposed wideband shorted planar inverted cone antenna (SPICA) has been described as a two element antenna array in this paper. The two element array by this antenna with proper phase of excitation and spacing between the elements provide superdirective array characteristic. This array gives peak endfire directivity from 3.502 dBi to 10.3 dBi and radiation efficiency above 98% in the operating frequency band. Also in radiation pattern characteristic, the farfield pattern of the array is more directional than single element array. Thus the proposed SPICA is suitable for wideband antenna array applications.
钢筋混凝土开孔深梁有限元分析与设计研究 Finite element analysis of RC deep beams with openings and researching of the design method

- , 2016, DOI: 10.7511/jslx201603006
Abstract: 钢筋混凝土深梁受力不同于浅梁,梁腹开孔后受力更趋复杂。现有的设计方法对深梁行为的解释不够完备,设计结果的适用性难以判断,设计规范也没有给出开孔深梁的设计条文。为研究深梁设计方法的有效性,本文采用了非线性有限元分析方法,引入适合混凝土结构非线性分析的断裂塑性模型,并考虑钢筋粘结滑移效应,对一系列开双孔或偏孔钢筋混凝土深梁试验进行仿真分析,所得结果与试验结果吻合良好,能够准确预测深梁在裂缝、破坏形态及承载力等方面的受力特征。研究表明现有的深梁设计方法中,压拉杆模型方法相较内力法和应力图形法更加经济有效。在仿真分析的基础上,提出了一种对开孔深梁具有普遍适用性的非线性设计方法,其设计结果具有高承载力、较好延性、经济的配筋量和充分的材料利用率的优点。
The behavior of reinforced concrete (RC) deep beams is different from shallow beams and the situation becomes more complex since the presence of web openings.All codes presented are short of explaining the exact behavior of deep beams and the scope of application.However,no code provision exists for the deep beams with openings.In this paper,nonlinear finite element analysis method is used to the effectiveness of design methods for RC deep beams,including reinforcement bond-slip model and fracture-plastic model,which is suitable for nonlinear analysis of concrete structures.A series of RC deep beams with openings,are analyzed and the simulation results are found agreed well with test results.And it can exactly predict such as cracks,failure modes and limit strengths.It finds out that strut-and-tie model (STM) method is more optimized than the internal forces method and the stress graphical method among the present design methods.Based on these results,a new nonlinear design method,generally applying to all deep beams with opening,is presented and proved the most optimized one when compared capacity,ductility,steel amount and material utilization with the others.
Inverted indexes-Types and techniques
Ajit Kumar Mahapatra,Sitanath Biswas
International Journal of Computer Science Issues , 2011,
Abstract: There has been a substantial amount of research on high performance inverted index because most web and search engines use an inverted index to execute queries. Documents are normally stored as lists of words, but inverted indexes invert this by storing for each word the list of documents that the word appears in, hence the name "inverted index". This paper presents the crucial research findings on inverted indexes, their types and techniques.
A. Zulkifli,A.K. Ariffin,M.M. Rahman
International Journal of Automotive and Mechanical Engineering , 2011,
Abstract: The major goal of this study is to determine the stress on vertebrae subjected to hyperextension loading. In addition, probabilistic analysis was adopted in finite element analysis (FEA) to verify the parameters that affected failure. Probabilistic finite element (PFE) analysis plays an important role today in solving engineering problems in many fields of science and industry and has recently been applied in orthopaedic applications. A finite element model of the L2 vertebra was constructed in SolidWorks and imported by ANSYS 11.0 software for the analysis. For simplicity, vertebra components were modelled as isotropic and linear materials. A tetrahedral solid element was chosen as the element type because it is better suited to and more accurate in modelling problems with curved boundaries such as bone. A Monte Carlo simulation (MCS) technique was performed to conduct the probabilistic analysis using a built-in probabilistic module in ANSYS with 100 samples. It was found that the adjacent lower pedicle region depicted the highest stress with 1.21 MPa, and the probability of failure was 3%. The force applied to the facet (FORFCT) variable needs to be emphasized after sensitivity assessment revealed that this variable is very sensitive to the stress and displacement output parameters.
Design of Infrared Inverted Telephoto-Optical System with Double-Layer Harmonic Diffractive Element
FAN Chang-Jiang,WANG Zhao-Qi,LIN Lie,ZHANG Mei,FAN Hai-Ying,

中国物理快报 , 2007,
Abstract: A double-layer harmonic diffractive element (HDE) structure is investigated and the optimization procedure is given based on the equation of diffraction efficiency of the double-layer diffractive optical element. A new infrared double-layer inverted telephoto-optical system with an HDE is designed, which can work in the mid- and far-infrared wavebands. The diffraction efficiency of the system at each wavelength in the designed two wavebands is larger than 90%, which improves the image contrast and the imaging quality significantly.
DYNA , 2011,
Abstract: this paper compares the performance of four isolated reinforced concrete (rc) walls with openings: two prototype walls tested under quasi-static cyclic (qsc) loading, and two models tested under shaking table excitation. the variables studied were the web steel ratio, the type of web reinforcement, and the testing method. by means of the measured response, it was verified that loading history of the qsc testing ignores the foremost dynamic effects observed in structures subjected to earthquake loads. when dynamic and qsc responses were compared, it was apparent that stiffness and strength degradation properties depend on the loading rate, the strength mechanisms associated to the failure modes, number of cycles, and cumulative parameters such as ductility demand and energy dissipated. we deducted that data obtained from qsc tests cannot always be safely assumed to be a lower limit of the expected capacity. stiffness and strength degradation models for rc walls with openings subjected to earthquake-type loading are also proposed.
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