scholarly journals Study on Partial Factor of Load for Reinforced Concrete Columns

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhengjie Cheng ◽  
Jitao Yao
Keyword(s):  
Structural Reliability ◽  
Design Method ◽  
Great Influence ◽  
Statistical Parameter ◽  
Simulation Method ◽  
Structure Design ◽  
Building Structures ◽  
Load Effect ◽  
Compression Members ◽  
Partial Factor

At present, the design method of components is still a partial factor design method, and the partial factor value is related to the load value. Because the partial factor has a great influence on the safety of engineering structure, it has been adjusted many times in the process of organization of the code. In order to be basically equivalent to European and American reliability standards and to conform to China’s national conditions and national policies, the Unified standard for reliability design of building structures is revised (i.e., the partial factor of permanent action and variable action was adjusted). Although the concept of factor of safety is commonly used in structure design practice to cover all the unexpected risks, there are some disadvantages to its direct use in structural reliability analysis. For example, the eccentricity of compression members is random, which will lead to the change in resistance parameters of compression members, rather than the fixed value specified in the code. However, the random variation in eccentricity is not considered in the code. So, in this paper, the partial factors of eccentrically loaded members are studied by considering the statistical parameter information of members with random eccentricity. This paper studies the partial factors of different types of components in different ratios of live load effect to dead load effect, and some recommendations are proposed to obtain safer designs. Finally, Monte Carlo simulation method is used to analyze the reliability of the eccentric member. The research results show that the value of partial factors of structure proposed in this paper is reasonable.

scholarly journals Component Combination Rules of Wind Load Effects of Building Structures

2020 ◽  
Vol 10 (24) ◽  
pp. 8775
Author(s):  
Haiwei Guan ◽  
Yuji Tian
Keyword(s):  
Extreme Values ◽  
Simulation Method ◽  
Wind Load ◽  
Combination Method ◽  
Wind Effect ◽  
Building Structures ◽  
Combination Rules ◽  
Load Effect ◽  
Mean Values ◽  
Standard Deviations

Under the action of the same wind azimuth, the extreme values of the wind load effect components of building structures are generated in the along-wind, cross-wind, vertical, and torsional directions. In designing the wind-resistant structure, the extreme values of effect components need to be combined to determine the internal force envelope values of members. Complete quadratic combination (CQC) and Turkstra combination rules are often used to determine the combination value of extreme values of wind effect components. The extreme probability distribution expressions of the CQC, and the Turkstra and approximate rules, are derived. The simplified combination Equations and combination coefficients of the CQC and Turkstra approximate rules are proposed in this paper. We use the combination Equations and Monte Carlo simulation method to analyze the accuracy of Turkstra and its approximate rules. The results show that the combination extreme is associated with the correlation coefficients, mean values, ratios of standard deviations, and fluctuating extremes of effect components. The errors between Turkstra and its approximate rules are small when load effect components show a positive correlation. The errors are largest when the standard deviations of components are equal. Our research results provide a theoretical basis for the combination method of wind load effect components of building structures.

Adaptive Synthesis of Hydraulic Circuits From Design Cases Based on Functional Structure

1995 ◽  
Author(s):  
Kikuo Fujita ◽  
Shinsuke Akagi ◽  
Makoto Sasaki
Keyword(s):  
Design Method ◽  
Synthesis Method ◽  
Simulation Method ◽  
Structure Design ◽  
Functional Structure ◽  
Case Based Reasoning ◽  
Symbol Manipulation ◽  
Case Base ◽  
Functional Structure Design ◽  
Hydraulic Circuits

Abstract An adaptive synthesis method for hydraulic circuits is proposed by using case-based reasoning technique based on their functional structure. Since synthesis of hydraulic circuits is a typical problem of conceptual design and its property is expertise-oriented and combinatorial, it is difficult to declaratively represent useful design knowledge. In our design method, past design cases are afore-stored in the case base, and then a circuit is generated by arranging suitable past cases which are retrieved from the case base in accordance with the difference related to functional structure. In order to measure such functional structure, design specifications are represented with labels. Design cases are adaptively manipulated into a target design with three synthesis strategies, decomposition, series combination and parallel combination, based on surplus or deficit of labels. Moreover, arranged circuits are verified with a logical simulation method based on symbol manipulation. These synthesis and simulation methods are applied to some design problems in order to show their effectiveness and validity.

scholarly journals Development and Performance Analysis of Pneumatic Soft-Bodied Bionic Actuator

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Wenchuan Zhao ◽  
Yu Zhang ◽  
Ning Wang
Keyword(s):  
Numerical Simulation ◽  
Silica Gel ◽  
Dynamic Characteristics ◽  
Design Method ◽  
Structural Characteristics ◽  
Simulation Method ◽  
Structure Design ◽  
Deformation Analysis ◽  
Analysis Model ◽  
Nonlinear Hyperelasticity

The design of a pneumatic soft-bodied bionic actuator derives from the structural characteristics and motion mechanism of biological muscles, combined with the nonlinear hyperelasticity of silica gel, which can improve the mobility and environmental adaptability of soft-bodied bionic robots. Based on Yeoh’s second-order constitutive model of silica gel, the deformation analysis model of the actuator is established, and the rationality of the structure design and motion forms of the actuator and the accuracy of the deformation analysis model are verified by using the numerical simulation algorithm. According to the physical model of the pneumatic soft-bodied bionic actuator, the motion and dynamic characteristics of the actuator are tested and analyzed, the curves of motion and dynamic characteristics of the actuator are obtained, and the empirical formula of the bending angle and driving torque of the actuator is fitted out. The results show that the deformation analysis model and numerical simulation method are accurate, and the pneumatic soft-bodied bionic actuator is feasible and effective, which can provide a design method and reference basis for the research and implementation of soft-bodied bionic robot actuator.

scholarly journals Analysis of Pathological Manifestations in Buildings at the University City Prof. José da Silveira Netto, Located in Belém-PA

2019 ◽  
Vol 8 (9S) ◽  
pp. 1016-1020
Keyword(s):  
Reinforced Concrete ◽  
Visual Analysis ◽  
Great Influence ◽  
Structure Design ◽  
Building Structures ◽  
University Campus ◽  
The North ◽  
University City ◽  
The University

The reinforced concrete structures are present in most constructions around the world and can be defined as a composite material of concrete reinforced with steel bars. Those structures may exhibit pathologies during the construction stage or after, due to several types of failures, whether is in the project, execution or maintenance. The Universidade Federal do Pará, has great influence over Brazil, being considered the biggest university in the north of the country. Despite its relevance, the university campus presents numerous problems in their building structures. The purpose of this paper is to identify the pathologies in the older and most recent reinforced concrete buildings existing at the Cidade Universitária Prof. José da Silveira Netto, Guamá campus, located in Belém, state's capital, enabling the evaluation of corrective maintenance needs of the most deteriorated constructions. To support the case study, it was performed a visual analysis with photographic register, allied to theoretical study regarding the subject, enabling the identification of possible causes of the alterations. The results show pathologies from many fields, from structure design until foundation of the buildings. The reduction in the occurrence of those manifestations would be possible, with better supervision during the construction process and preventive maintenance, whose lack of were the main cause of the identified pathologies.

scholarly journals Erosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1540
Author(s):  
Qianqian Ji ◽  
Zhe Gao ◽  
Xingyao Li ◽  
Jian’en Gao ◽  
Gen’guang Zhang ◽  
...  
Keyword(s):  
Similarity Theory ◽  
Design Method ◽  
Simulation Method ◽  
Practical Significance ◽  
Land Consolidation ◽  
Small Watershed ◽  
Flood Peak ◽  
Erosion Area ◽  
The Impact ◽  
Erosion Environment

The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: λl = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW.

scholarly journals Comparison of reliability evaluation methods between China and Canada standards for wood structures featuring duration of load

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
Qiongyao Wu ◽  
Shuang Niu ◽  
Enchun Zhu
Keyword(s):  
Reliability Analysis ◽  
Analysis Method ◽  
Safety Level ◽  
Wood Structures ◽  
Load Effect ◽  
Key Factor ◽  
Live Loads ◽  
High Level ◽  
Partial Factor ◽  
Duration Of Load

Abstract Duration of load (DOL) is a key factor in design of wood structures, which makes the reliability analysis of wood structures more complicated. The importance of DOL is widely recognized, yet the methods and models through which it is incorporated into design codes vary substantially by country/region. Few investigations of the effect of different model assumptions of DOL and other random variables on the results of reliability analysis of wood structures can be found. In this paper, comparisons are made on the reliability analysis methods that underlie the China and the Canada standards for design of wood structures. Main characteristics of these two methods, especially the way how DOL is treated are investigated. Reliability analysis was carried out with the two methods employing the same set of material properties and load parameters. The resulted relationships between reliability index β and resistance partial factor γR* (the β–γR* curves) for four load combinations are compared to study the safety level indicated by the two methods. The comparison shows that the damage accumulation model (Foschi–Yao model) in the Canada analysis method is highly dependent on the type and duration of load, resulting in more conservative design than the China analysis method in loading cases dominated by dead load, but less conservative design in cases of high level of live loads. The characteristics of the load effect term of the performance function are also found to make considerable difference in reliability levels between the two methods. This study aims to provide references for researchers and standard developers in the field of wood structures.

scholarly journals Multi-Branch Cable Harness Layout Design Based on Genetic Algorithm with Probabilistic Roadmap Method

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Yingfeng Zhao ◽  
Jianhua Liu ◽  
Jiangtao Ma ◽  
Linlin Wu
Keyword(s):  
Genetic Algorithm ◽  
Topological Structure ◽  
Design Method ◽  
Route Planning ◽  
Layout Design ◽  
Structure Design ◽  
Prototype System ◽  
Cable Harness ◽  
Probabilistic Roadmap ◽  
Probabilistic Roadmap Method

AbstractCurrent studies on cable harness layouts have mainly focused on cable harness route planning. However, the topological structure of a cable harness is also extremely complex, and the branch structure of the cable harness can affect the route of the cable harness layout. The topological structure design of the cable harness is a key to such a layout. In this paper, a novel multi-branch cable harness layout design method is presented, which unites the probabilistic roadmap method (PRM) and the genetic algorithm. First, the engineering constraints of the cable harness layout are presented. An obstacle-based PRM used to construct non-interference and near to the surface roadmap is then described. In addition, a new genetic algorithm is proposed, and the algorithm structure of which is redesigned. In addition, the operation probability formula related to fitness is proposed to promote the efficiency of the branch structure design of the cable harness. A prototype system of a cable harness layout design was developed based on the method described in this study, and the method is applied to two scenarios to verify that a quality cable harness layout can be efficiently obtained using the proposed method. In summary, the cable harness layout design method described in this study can be used to quickly design a reasonable topological structure of a cable harness and to search for the corresponding routes of such a harness.

Calculation and Design Method Study of the Coil-Wound Heat Exchanger

2014 ◽  
Vol 1008-1009 ◽  
pp. 850-860 ◽  
Author(s):  
Zhou Wei Zhang ◽  
Jia Xing Xue ◽  
Ya Hong Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Design Method ◽  
Fluid Velocity ◽  
Exchange Process ◽  
Three Dimensional ◽  
Simulation Method ◽  
Physical Parameters ◽  
Numerical Result

A calculation method for counter-current type coil-wound heat exchanger is presented for heat exchange process. The numerical simulation method is applied to determine the basic physical parameters of wound bundles. By controlling the inlet fluid velocity varying in coil-wound heat exchanger to program and calculate the iterative process. The calculation data is analyzed by comparison of numerical result and the unit three dimensional pipe bundle model was built. Studies show that the introduction of numerical simulation can simplify the pipe winding process and accelerate the calculation and design of overall configuration in coil-wound heat exchanger. This method can be applied to the physical modeling and heat transfer calculation of pipe bundles in coil wound heat exchanger, program to calculate the complex heat transfer changing with velocity and other parameters, and optimize the overall design and calculation of spiral bundles.

Based on the Grey Relation Analysis of Ecological Composite Wall Seismic Performance Research

2013 ◽  
Vol 368-370 ◽  
pp. 1043-1047
Author(s):  
Yin Zhang ◽  
You Han ◽  
Shuai Liang
Keyword(s):  
Seismic Performance ◽  
Evaluation System ◽  
Design Method ◽  
Structure Design ◽  
Grey System Theory ◽  
Frame Structure ◽  
Wall Structure ◽  
Width Ratio ◽  
Grey System ◽  
Composite Wall

Ecological composite wall as ecological composite wall structure of the main stress components, the seismic performance is ecological composite wall structure seismic performance evaluation system of the main content. Based on the grey system theory, the grey correlation analysis to the key parameters (the mouth of the cave, frame structure, height to width ratio) change ecological composite wall test results are analyzed, the key parameters on the ecological composite wall the influence law of seismic performance, for choosing wall structure design method to provide basis.

Modular Design Technology of Multi-DOF Mechanical Arm

2014 ◽  
Vol 599-601 ◽  
pp. 358-361
Author(s):  
Huan Qiang ◽  
Hu Zhang ◽  
Yan Zhou
Keyword(s):  
Modular Design ◽  
Design Method ◽  
Structure Design ◽  
Degree Of Freedom ◽  
Dynamics Simulation ◽  
Complicated Structure ◽  
Design Technology ◽  
Structure Line ◽  
Six Dof

A design method of modular joint is proposed according to the complicated structure, line exposed and heavier characteristics of multi-DOF (degree of freedom) mechanical arm. In this paper, the design of modular joint was carried on and a model of six-DOF mechanical arm was built through the research on the structure of mechanical arm. On this basis, dynamics simulation will be carried. The results show that the modular design method simplified the structure of the mechanical arm, the dynamics simulation proved it was feasible for the structure design and drive selection.

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