scholarly journals Experimental and Reliability-Based Investigation on Sheathing-to-Framing Joints under Monotonic and Cyclic Loads

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 995
Author(s):  
Jing Di ◽  
Hongliang Zuo
Keyword(s):  
Bearing Capacity ◽  
Reliability Index ◽  
Bending Strength ◽  
Design Method ◽  
Frame Structure ◽  
Reliability Method ◽  
Modification Factor ◽  
Design Value ◽  
Wood Frame ◽  
Strength And Stiffness

The seismic performance of a light wood frame structure is determined by sheathing-to-framing joints. In order to encourage the use of more sustainable materials in structures, the spruce-pine-fir (SPF) panel and the bamboo scrimber (BS) panel were considered as sheathing materials. Monotonic and cyclic tests were conducted on the joints with different parameters to obtain their mechanical properties. Moreover, the design value of the bearing capacity of sheathing-to-framing joints was calculated and compared in accordance with Chinese code (GB50005) and European code (Eurocode 5). Based on the test results and the design codes, the reliability index of the design value of the bearing capacity of joints was calculated using the first-order reliability method (FORM). Results demonstrate that the joints have high bearing capacity and stiffness at initial loading stage when the loading direction is perpendicular to the framing grain. BS panels make better use of the bending strength of fasteners than SPF panels. The screwed joints have lower strength and stiffness degradation than nailed joints, but the nailed joints show better ductile and dissipation than screwed joints. In addition, the reliability indexes of design bearing capacity calculated by the Chinese code of joints under monotonic load are conservative, but those of joints under cyclic load are unconservative. Therefore, in order to ensure the safety and economy of design, a modification factor for the GB50005 design method of joints is proposed to meet the target reliability index.

Reliability Analysis of Subgrade Bearing Capacity of Gravity Foundation of Wind Turbine Based on JC Method

2011 ◽  
Vol 413 ◽  
pp. 314-319
Author(s):  
Zhong Qing Cheng ◽  
Ping Yang ◽  
Hai Bo Jiang
Keyword(s):  
Bearing Capacity ◽  
Wind Turbine ◽  
Reliability Analysis ◽  
Reliability Index ◽  
Maximum Pressure ◽  
Performance Function ◽  
Iterative Calculation ◽  
Reliability Method ◽  
Foundation Base ◽  
Index Effect

The design of foundation of wind turbine should meet the requirement of subgrade bearing capacity. In this paper, reliability method was used to analyze the bearing capacity of gravity foundation of wind turbine. The circular gravity foundation in coral sands is taken as research object. By deriving the expression of maximum pressure at the edge of foundation base under the action of overturning moment, the performance function of subgrade bearing capacity reliability analysis is established. JC method is used to calculate the subgrade bearing capacity reliability index. Effect of foundation size to reliability index is analyzed. Iterative calculation shows that the method proposed in this paper can calculate the reliability index of foundation quickly.

Seismic design of hybrid unbonded post-tensioned precast concrete joints based on bearing capacity and energy dissipation capacity

2020 ◽  
pp. 136943322098273
Author(s):  
Baoxi Song ◽  
Weizhi Xu ◽  
Dongsheng Du ◽  
Shuguang Wang ◽  
Weiwei Li ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Design Method ◽  
Precast Concrete ◽  
Residual Deformation ◽  
Time History ◽  
Frame Structure ◽  
Energy Dissipation Capacity ◽  
Concrete Joints ◽  
Post Tensioned

This paper provides a practical design method for hybrid unbonded post-tensioned precast concrete joints. Such joints featured with self-centering capacities have been widely favored in recent years. However, the absence of design methods hinders their further promotion. To solve the issue, two methods for calculating mechanical behavior of the joints were first studied: characteristic points method and iterative method. The effectiveness of the methods was verified by the existing test results. On this basis, a joint design method considering both yield bearing capacity and energy dissipation capacity was proposed. Moreover, to facilitate design, some factors affecting the bearing capacity were discussed. A five-story frame structure was designed by the proposed design method, and the influence of two design factors on structural response was analyzed by utilizing nonlinear time-history method. The analysis results show that: with the increase of energy dissipation factor αs, the post-earthquake residual deformation of the structure tends to increase linearly, while the accumulated damage of the structure will decrease continuously; both overdesign and underdesign of bearing capacity of the joint are unfavorable; and near-field earthquake may cause irreparable damage to structural columns, making the residual deformation of structures contrary to the self-centering capacity of joints, which shall be considered during engineering design.

Reliability Method and its Standard of the Composite Foundation Bearing Capacity

2012 ◽  
Vol 170-173 ◽  
pp. 144-147
Author(s):  
Xiao Yun Peng ◽  
Peng Ju Cui
Keyword(s):  
Bearing Capacity ◽  
Reliability Analysis ◽  
Reliability Index ◽  
Limit State ◽  
State Equation ◽  
Composite Foundation ◽  
Analysis Method ◽  
Cement Injection ◽  
Reliability Method ◽  
General Reliability

The general reliability analysis method of composite foundation bearing capacity was established with the example of cement injection pile, its limit state equation and the optimize method was presented, and the standard of reliability index was also proposed according to the corresponding demand of architectural structure. It indicate that the method is reasonable, convenient to calculation and can be popularized in the whole geotechnical engineering.

Design and Research of Double-Drum Winch with Anti-Pressure Wheel

2012 ◽  
Vol 479-481 ◽  
pp. 1709-1713
Author(s):  
Kai An Yu ◽  
Tao Yang ◽  
Chang Zhi Gong
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Finite Element Methods ◽  
Design Method ◽  
New Method

In view of the problems of large stress and severe bearing heating in double-drum winch at present, this paper adopted a new method to enhance bearing capacity for double-drum winch by adding anti-pressure wheels between two drums. Finite element methods were used to analyze the strength of 4000kN-traction double-drum winches with anti-pressure wheels and without anti-pressure wheels respectively. The results of the analysis revealed that the stress of the cylinder bearing decreased from 264MPa to 167MPa. The new method by adding anti-pressure wheels had remarkably improved the endurance of the bearing. Therefore, the design method can be widely used in large-traction double-drum winch.

scholarly journals Lightweight and maintainable rotary-wing UAV frame from configurable design to detailed design

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110349
Author(s):  
Huiqiang Guo ◽  
Mingzhe Li ◽  
Pengfei Sun ◽  
Changfeng Zhao ◽  
Wenjie Zuo ◽  
...  
Keyword(s):  
Design Method ◽  
Geometric Model ◽  
Optimization Method ◽  
Frame Structure ◽  
Manufacturing Cost ◽  
Detailed Design ◽  
High Manufacturing Cost ◽  
The Military ◽  
Rotary Wing ◽  
Novel Design

Rotary-wing unmanned aerial vehicles (UAVs) are widespread in both the military and civilian applications. However, there are still some problems for the UAV design such as the long design period, high manufacturing cost, and difficulty in maintenance. Therefore, this paper proposes a novel design method to obtain a lightweight and maintainable UAV frame from configurable design to detailed design. First, configurable design is implemented to determine the initial design domain of the UAV frame. Second, topology optimization method based on inertia relief theory is used to transform the initial geometric model into the UAV frame structure. Third, process design is considered to improve the manufacturability and maintainability of the UAV frame. Finally, dynamic drop test is used to validate the crashworthiness of the UAV frame. Therefore, a lightweight UAV frame structure composed of thin-walled parts can be obtained and the design period can be greatly reduced via the proposed method.

Some Important Issues on First-Order Reliability Analysis With Nonprobabilistic Convex Models

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
C. Jiang ◽  
G. Y. Lu ◽  
X. Han ◽  
R. G. Bi
Keyword(s):  
Reliability Analysis ◽  
Reliability Index ◽  
Probability Model ◽  
Mean Value ◽  
Convex Model ◽  
First Order ◽  
Reliability Method ◽  
Complex Engineering ◽  
Mean Value Method ◽  
Form Type

Compared with the probability model, the convex model approach only requires the bound information on the uncertainty, and can make it possible to conduct the reliability analysis for many complex engineering problems with limited samples. Presently, by introducing the well-established techniques in probability-based reliability analysis, some methods have been successfully developed for convex model reliability. This paper aims to reveal some different phenomena and furthermore some severe paradoxes when extending the widely used first-order reliability method (FORM) into the convex model problems, and whereby provide some useful suggestions and guidelines for convex-model-based reliability analysis. Two FORM-type approximations, namely, the mean-value method and the design-point method, are formulated to efficiently compute the nonprobabilistic reliability index. A comparison is then conducted between these two methods, and some important phenomena different from the traditional FORMs are summarized. The nonprobabilistic reliability index is also extended to treat the system reliability, and some unexpected paradoxes are found through two numerical examples.

Barrier Function Method in Reliability Based Design Optimization

2005 ◽  
Vol 297-300 ◽  
pp. 1882-1887
Author(s):  
Tae Hee Lee ◽  
Jung Hun Yoo
Keyword(s):  
Design Optimization ◽  
Barrier Function ◽  
Reliability Index ◽  
Feasible Solution ◽  
Reliability Based Design Optimization ◽  
User Requirement ◽  
Mean Values ◽  
Reliability Based Design ◽  
Design Variables ◽  
Reliability Method

In practical design applications, most design variables such as thickness, diameter and material properties are not deterministic but stochastic numbers that can be represented by their mean values with variances because of various uncertainties. When the uncertainties related with design variables and manufacturing process are considered in engineering design, the specified reliability of the design can be achieved by using the so-called reliability based design optimization. Reliability based design optimization takes into account the uncertainties in the design in order to meet the user requirement of the specified reliability while seeking optimal solution. Reliability based design optimization of a real system becomes now an emerging technique to achieve reliability, robustness and safety of the design. It is, however, well known that reliability based design optimization can often have so multiple local optima that it cannot converge into the specified reliability. To overcome this difficulty, barrier function approach in reliability based design optimization is proposed in this research and feasible solution with specified reliability index is always provided if a feasible solution is available. To illustrate the proposed formulation, reliability based design optimization of a bracket design is performed. Advanced mean value method and first order reliability method are employed for reliability analysis and their optimization results are compared with reliability index approach based on the accuracy and efficiency.

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