• Advances in Computational Design
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• v.2 no.1
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• pp.15-28
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• 2017

One of the major developments in seismic design over the past few decades is the increased emphasis for limit states design now generally termed as Performance Based Engineering. Performance Based Seismic Design (PBSD) uses Displacement Based Design (DBD) methodology wherein structures are designed for a target level of displacement rather than Force Based Design (FBD) methodology where force or strength aspect is being used. Indian codes still follow FBD methodology compared to other modern codes like CalTrans, which follow DBD methodology. Hence in the present study, a detailed review of the two most common design methodologies i.e., FBD and DBD is presented. A critical evaluation of both these methodologies by comparing the seismic performance of bridge models designed using them highlight the importance of adopting DBD techniques in Indian Standards also. The inherent discrepancy associated with FBD in achieving 'seismic regularity' is highlighted by assessing the seismic performance of bridges with varied relative height ratios. The study also encompasses a brief comparison of the seismic design and detailing provisions of IRC 112 (2011), IRC 21 (2000), AASHTO LRFD (2012) and CalTrans (2013) to evaluate the discrepancies on the same in the Indian Standards. Based on the seismic performance evaluation and literature review a need for increasing the minimum longitudinal reinforcement percentage stipulated by IRC 112 (2011) for bridge columns is found necessary.

• Advances in Computational Design
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• v.2 no.1
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• pp.43-56
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• 2017

The aim of this paper is to develop software for designing of steel reinforced elastomeric isolator (SREI) according to American Association for State Highway and Transportation Officials Load and Resistance Factor Design (AASHTO LRFD) Specifications. SREI is used for almost all bridge types and special structures. SREI-structures interface defines support boundary conditions and may affect the seismic performance of bridges. Seismic performance of the bridge is also affected by geometrical and materials properties of SREI. The selection of SREI is complicated process includes satisfying all the design constraints arising from code provisions and maximizing performance at the lowest possible cost. In this paper, design stage of SREI is described up to AASHTO LRFD 2012. Up to AASHTO LRFD 2012 analysis and design program of SREI performed different geometrical and material properties are created with C# object-oriented language. SREI-CAD, name of the created software, allows an accurate design for economical estimation of a SREI in a short time. To determine types of SREI effects, two different types of bearings, rectangular and circular with similar materials and dimension properties are selected as an application. Designs of these SREIs are completed with SREI-CAD. It is seen that ensuring the stability of circular elastomer bearing at the service limit state is generally complicated than rectangular bearing.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.148-152
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• 2006

Comparison of four phenolic compounds among three different parts of Panax ginseng C.A. Meyer was performed in this study. Contents of esculetin, p-coumaric acd, quercetin, maltol in the ethyl acetate fraction were determinated by HPLC analysis. The main root has a highest concentration of p-coumaric acid and the leave has a highest concentration of quercetin and esculetin. This ethyl acetate fraction of the leaves exhibited higher depigmenting activity and lower cell toxicity than the other parts of ginseng. In addition, it showed that quercetin and esculetin among phenolic compounds highly inhibited melanin biosynthesis in ginseng. It implies that leaves of ginseng may be used as skin whitening herb. Quercetin and esculetin proved to be active compounds in the leaves of ginseng.

• Advances in Computational Design
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• v.2 no.4
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• pp.257-271
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• 2017

There are many plain concrete arch bridges in Iran that have been used as railway bridges for more than seventy years. Owe to the fact that these bridges have not been designed seismically, and even may be loaded under high-speed trains, evaluation of fundamental frequencies of the bridges against earthquake and high-speed train vibrations is necessary for considering dynamics effects. To evaluate complex behavior of these bridges, results of field tests are useful. Since it is not possible to perform field tests for all arch bridges, these structures should be simulated correctly by computers for structural assessment. Several parameters are employed to describe the bridges, such as number of spans, length of spans, geometrical and material properties. In this study, results of field tests are used for modal analysis and adapted for 64 three dimensional finite element models with various physical parameters. Computer simulations show length of spans has important effect on fundamental frequencies of plain concrete arch bridge and modal deformations of bridges is in longitudinal and transverse directions. Also, these results demonstrate that fundamental frequencies of bridges decrease after increasing span length and number of spans. Plus, some relations based in the number of spans (n) and span length (l) are proposed for calculation of fundamental frequencies of plain concrete arch bridge.

• Advances in Computational Design
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• v.2 no.4
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• pp.313-331
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• 2017

In this study, teaching-learning based optimization (TLBO) is improved by incorporating model of multiple teachers, adaptive teaching factor, self-motivated learning, and learning through tutorial. Modified TLBO (MTLBO) is applied for simultaneous topology, shape, and size optimization of space and planar trusses to study its effectiveness. All the benchmark problems are subjected to stress, displacement, and kinematic stability constraints while design variables are discrete and continuous. Analyses of unacceptable and singular topologies are prohibited by seeing element connectivity through Grubler's criterion and the positive definiteness. Performance of MTLBO is compared to TLBO and state-of-the-art algorithms available in literature, such as a genetic algorithm (GA), improved GA, force method and GA, ant colony optimization, adaptive multi-population differential evolution, a firefly algorithm, group search optimization (GSO), improved GSO, and intelligent garbage can decision-making model evolution algorithm. It is observed that MTLBO has performed better or found nearly the same optimum solutions.

• Advances in Computational Design
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• v.2 no.4
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• pp.283-291
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• 2017

High frequency full bridge series resonant inverters have become increasingly popular among power supply designers. One of the most important parameter for a High Frequency Full Bridge Series Resonant Inverter is optimal coil design. The optimal coil designing procedure is not a easy task. This paper deals with the New Approach to Optimal Design Procedure for a Real-time High Frequency Full Bridge Series Resonant Inverter in Induction Heating Equipment devices. A new design to experimental modelling of the physical properties and a practical power input simulation process for the non-sinusoidal input waveform is accepted. The design sensitivity analysis with Levenberg-Marquardt technique is used for the optimal design process. The proposed technique is applied to an Induction Heating Equipment devices model and the result is verified by real-time experiment. The main advantages of this design technique is to achieve more accurate temperature control with a huge amount of power saving.

• Advances in Computational Design
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• v.2 no.4
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• pp.333-348
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• 2017

Inspections of ancient metallic bridges have illustrated fatigue cracking in riveted connections. This paper presents a comparison between two alternative finite element (FE) models proposed to predict the fatigue strength of a single shear and single rivet connection. The first model is based on solid finite elements as well as on contact elements, to simulate contact between the components of the connection. The second model is built using shell finite elements in order to model the plates of the riveted connection. Fatigue life predictions are carried out for the shear splice, integrating both crack initiation and crack propagation lives, resulting from the two alternative FE models. Global fatigue results, taking into account several clamping stresses on rivet, are compared with available experimental results. Proposed comparisons between predictions and experimental data illustrated that the proposed two-stage model yields consistent results.

• Advances in Computational Design
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• v.1 no.1
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• pp.1-25
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• 2016

Domes are architectural and elegant structures which cover a vast area with no interrupting columns in the middle, and with suitable shapes can be also economical. Domes are built in a wide variety of forms and specialized terms are available to describe them. According to their form, domes are given special names such as network, lamella, Schwedler, ribbed, and geodesic domes. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The network, lamella, ribbed and Schwedler domes are studied to determine the optimum number of rings, the optimum height of crown and tubular sections of these domes. The minimum volume of each dome is taken as the objective function. A simple procedure is defined to determine the dome structures configurations. This procedure includes calculating the joint coordinates and element constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). The wind loading act on domes according to ASCE 7-05 (American Society of Civil Engineers). This paper will explore the efficiency of various type of domes and compare them at the first stage to investigate the performance of these domes under different kind of loading. At the second stage the wind load on optimum design of domes are investigated for Schwedler dome. Optimization process is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for domes.

• Advances in Computational Design
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• v.1 no.1
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• pp.105-117
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• 2016

The objective of this work is to study the restraining effect in fire resistance of framed structures and to evaluate the global response of reinforced concrete frames when exposed to fire based on advanced finite element method. To study the response a single portal frame is analyzed. The effect of floor slab on this frame is studied by modeling a beam-column-slab assembly. The evolution of temperature distribution, internal stresses and deformations of the frame subjected to ISO 834 standard fire curve for both the frames are studied. The thermal and structural responses are evaluated and a comparison of results of individual members and entire structure is done. From the study it can be seen that restraining forces has significant influence on both stresses and deflection and overall response of the structure when compared to individual structural member. Among the various structural elements, columns are the critical members in fire and failure of column causes the failure of entire structure. The fire rating of various structural elements of the frame is determined by various failure criteria and is compared with IS456 2000 tabulated fire rating.

• Advances in Computational Design
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• v.1 no.1
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• pp.61-77
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• 2016

Seismic performance of structures depends on the force flow mechanism inside the structure. Discontinuity regions, like beam-column joints, are often affected during earthquake event due to the complex and discontinuous load paths. The evaluation of shear strength and identification of failure mode of the joint region are helpful to (i) define the strength hierarchy of the beam-column sub-assemblage, (ii) quantify the influence of different parameters on the behaviour of beam-column joint and, (iii) develop suitable and adequate strengthening scheme for the joints, if required, to obtain the desired strength hierarchy. In view of this, it is very important to estimate the joint shear strength and identify the failure modes of the joint region as it is the most critical part in any beam-column sub-assemblage. One of the most effective models is softened strut and tie model which was developed by incorporating force equilibrium, strain compatibility and constitutive laws of cracked reinforced concrete. In this study, softened strut and tie model, which incorporates force equilibrium equations, compatibility conditions and material constitutive relation of the cracked concrete, are used to simulate the shear strength behaviour and to identify failure mechanisms of the beam-column joints. The observations of the present study will be helpful to arrive at the design strategy of the joints to ensure the desired failure mechanism and strength hierarchy to achieve sustainability of structural systems under seismic loading.