Experimental Study and Calculation Model Analysis of the Temporary Stand Support Frame with Plug-in Joints

Experimental study on bond behavior between wet lay-up CFRP and corroded steel plates

A numerical study on load effects of low-rise buildings in a wind-blown sand environment

This paper provides a simple numerical method to determine the optimal parameters of tuned mass damper (TMD) and viscoelastic dampers (VEDs) in frame structure for wind vibration control considering the soil-structure interation (SSI) effect in frequency domain. Firstly, the numerical model of frame structure equipped with TMD and VEDs considering SSI effect is established in frequency domain. Then, the genetic algorithm (GA) is applied to obtain the optimal parameters of VEDs and TMD. The optimization process is demonstrated by a 20-storey frame structure supported by pile group for different soil conditions. Two wind resistant systems are considered in the analysis, the Structure-TMD system and the Structure-TMD-VEDs system. The example proves that this method can quickly determine the optimal parameters of energy dissipation devices compared with the traditional finite element method, thus is practically valuable.

The accurate modeling of uncertain variables, such as wind power and load uncertainty, is an essential foundation for the planning operation and scheduling decisions in power systems. Currently, Gaussian mixture model (GMM) and Dirichlet process mixture model (DPMM) are the primary techniques used to characterize uncertainties in power systems, which are commonly solved by expectation-maximization (EM) algorithm. However, for the massive data of uncertain variables, the algorithm encounters challenges in accurately obtaining GMM and DPMM with a lower time consumption. To address this issue, we propose a method for GMM uncertainty modeling in power systems considering the mutual assistance of latent variables. Specifically, the GMM of uncertain variables is first constructed, and the conditional probability is employed to characterize the mutual assistance of latent variables. Then, an improved EM algorithm is developed to obtain the optimal GMM parameters, in which the expectation step (E-step) and maximization step (M-step) of the algorithm are revised using the conditional probability. Importantly, the closed-form solutions for GMM parameters are rederived in the revised E-step and M-step. Finally, the proposed uncertainty modeling method is compared with the traditional GMM and DPMM on actual wind power and load data from Australia. The proposed method performs the efficiency and accuracy in characterizing uncertainty.

The objective of this study was to evaluate appropriate test methods for the bearing properties of wood peg connection using four different test methods: ASTM D 5764 (2013), the method of Church and Tew (1997), the method of Schmidt and Daniels (1999), and the method of Schmidt and Mackay (1997). Bearing properties of wood peg connection were compared using digital image correlation. Although ASTM D 5764 (2013), the method of Church and Tew (1997), or the method of Schmidt and Daniels (1999) could not differentiate bearing properties by peg orientation, the method of Schmidt and Mackay (1997) could differentiate such properties by peg orientation. ASTM D 5764 (2013), the method of Church and Tew (1997), and the method of Schmidt and Daniels (1999) created unrealistic strain distributions which affected yield load determined from the load–displacement curve. The method of Schmidt and Mackay (1997) showed the highest strain distribution at the bearing area between the wood peg and the main member, resulting in load–displacement curve by bearing mainly. These results suggest that the method of Schmidt and Mackay (1997) could determine the bearing properties of wood peg connection.

Geogrids significantly enhance the soil matrix stability and foundation bearing capacity. Despite the development of numerous geogrid configurations, their geometric design has not yet been systematically optimized. The design of geogrid aperture geometry aims to maximize geogrid performance while maintaining material efficiency. Nevertheless, topology optimized geogrid designs remain underexplored, particularly regarding the influence of aperture shape on interface shear behavior. To address this gap, this study developed SIMP-based variable density topology optimization models for three types of tensile geogrid structures: uniaxial, biaxial, and triaxial geogrid. The effects of key model parameters on the optimization results are examined, resulting in new geogrid geometries optimized primarily to minimize compliance, achieving weight reductions of 7%, 10%, and 12%, respectively. Subsequently, FLAC3D was used for tensile performance analysis, while coupled PFC3D–FLAC3D was employed for interfacial friction performance analysis. In FLAC3D, numerical simulations demonstrated that the topologically optimized geogrid outperformed conventional ones in both tensile resistance and strain distribution. Consequently, conventional biaxial and triaxial geogrids, along with their topologically optimized versions, were chosen for further analysis. Pull-out interface simulations of these geogrids were conducted using the coupled discrete element–finite difference method (PFC3D–FLAC3D) to investigate the influence of geogrid aperture shape and aperture ratio on the soil–geogrid interface. The results indicate that the reinforcement efficiency of the topologically optimized biaxial and triaxial geogrids was 10% and 8% higher, respectively, than that of the conventional geogrids. Taking the biaxial geogrid as an example, a comprehensive comparison of performance parameters between the conventional and topology-optimized versions revealed that the optimized design achieved a 10% reduction in weight. Simultaneously, it reduced stress concentration at critical locations by approximately 60% and increased the interface pull-out resistance by 20%. These findings demonstrate that the new topologically optimized geogrid exhibits significant potential for further promotion and application in practical engineering.

Effects of various reinforcing intra-module connection details on seismic behavior of corner-supported steel modular buildings

Multi-objective optimization of a structural link for a linked tall building system

According to the investigation of earthquake damages in China and abroad, the earthquake resistant behavior of frame shear wall structure is better than that of frame structure. Compared to the reinforced concrete fame shear wall structure, the fame structure is easier to be damaged under the action of earthquakes. In this paper, the five-storey frame structure model is taken as the research object, and a certain number of shear walls are reasonably arranged to form a frame shear wall structure to compare and analyze the earthquake resistant behavior of the two structures. The analysis results show that the frame shear wall structure can achieve good earthquake resistant behavior compared with the frame structure.

This paper presents a shaking table test carried out on a 1:5 reduced-scale five-story masonry-infilled reinforced concrete (RC) frame model. Multi-level simulated earthquake motions with increasing shaking severity were used as input to deform the model structure from an elastic to a near-collapse state. The dynamic characteristics, acceleration response, displacement response, damage state, energy dissipation behavior and stiffness degradation of each story were summarized for each stage. The tests indicate that cracks developed at the masonry-frame interface during minor shaking that caused infill to separate from the frame; however, its in-plane load bearing capacity was maintained. Moreover, the infill was able to resist infrequent earthquakes without causing instability or collapse of the structure. Thus, it is rational to consider masonry infill as a structural element in the seismic design of structures. Moreover, the story drift ratio of 1/400 can be regarded as the performance criterion for controlling frame structure cracking, and the story drift ratio of 1/100 can be regarded as the performance criterion for the peak bearing capacity of a frame structure. The test results could provide a reference not only for the seismic appraisal of existing buildings, but also for the seismic design of new buildings.

The high frequency base balance (HFBB) technique is a convenient and relatively fast wind tunnel testing technique for predicting wind-induced forces for tall building design. While modern tall building design has seen a number architecturally remarkable buildings constructed recently, the characteristics of those buildings are significantly different to those that were common when the HFBB technique was originally developed. In particular, the prediction of generalized forces for buildings with 3-dimensional mode shapes has a number of inherent uncertainties and challenges that need to be overcome to accurately predict building loads and responses. As an alternative to the more conventional application of general mode shape correction factors, an analysis methodology, referred to as the linear-mode-shape (LMS) method, has been recently developed to allow better estimates of the generalized forces by establishing a new set of centers at which the translational mode shapes are linear. The LMS method was initially evaluated and compared with the methods using mode shape correction factors for a rectangular building, which was wind tunnel tested in isolation in an open terrain for five incident wind angles at <TEX>$22.5^{\circ}$</TEX> increments from <TEX>$0^{\circ}$</TEX> to <TEX>$90^{\circ}$</TEX>. The results demonstrated that the LMS method provides more accurate predictions of the wind-induced loads and building responses than the application of mode shape correction factors. The LMS method was subsequently applied to a tall building project in Hong Kong. The building considered in the current study is located in a heavily developed business district and surrounded by tall buildings and mixed terrain. The HFBB results validated the versatility of the LMS method for the structural design of an actual tall building subjected to the varied wind characteristics caused by the surroundings. In comparison, the application of mode shape correction factors in the HFBB analysis did not directly take into account the influence of the site specific characteristics on the actual wind loads, hence their estimates of the building responses have a higher variability.

Design analysis of chassis especially electric mass transportation was very crucial due to the addition of battery pack weight about a half of total vehicle weight. This present study aims to redesign, simulate and perform the stress analysis of the structural mini bus chassis by using Finite Element Analysis (FEA). The main chassis was reinforced by the battery support structure frame of the removable battery pack to achieve optimal safety factor at maximum total load. Maximum loads were varied, they were 3.6, 4, 4.5, and 5 ton. The material also varied, ASTM A302 and ASTM A710. It found that high stress and maximum deflection area locations in chassis were identified as weakness area, and it needs to recover by the addition of the battery support structure frame. The best structure frame is the lightest structure with the highest safety factor and achieved above 1 level of safety factor. Also, the maximum deflection was tolerated. The result of FEA simulation was showed that the selected design of support frame was the best design for electric mini bus and it became reference for future design.

Contributions to member stresses due to overall wind-induced behaviors of thin-walled cylindrical shell

For the crawling problems of the changing-wheel device,the paper put forward a single-degree-of-freedom spring-quality system of a physical model of crawling motion,and described the model mathematically.Than the paper analyzed the main factors which produced several crawl,and obtained the displacement and velocity response curve of the system model,and coincide with the motion state results of the actual light rail in the changing-wheel library device. The paper built a simplified hydraulic system model of the rotary device,and made simulation analysis for the hydraulic system model through the Matlab,found the main factors which influence the crawling system is driving speed (force),vertical load, system stiffness and system damping,than given some methods which can help restrain the crawling. After the simply analyzed for the characteristics of throttle valve,the paper made some optimization for the original hydraulic system,that is at the hydraulic back oil piping,joining the throttle to the components,which purpose is to increase the effective damping of the system,thus inhibiting system to crawl.This optimization already have been proved through the practical engineering application.

Energy sustainability of hybrid energy systems is essentially a multi-objective, multi-constraint problem, where the energy system requires the capability to make rapid and robust decisions regarding the dispatch of electrical power produced by generation assets. This process of control for energy system components is known as energy management. In this paper, the application of particle swarm optimization (PSO), which is a biologically-inspired direct search method, to find real-time optimal energy management solutions for a stand-alone hybrid wind microturbine energy system is presented. Results demonstrate that the proposed PSO-based energy management algorithm can solve an extensive solution space while incorporating many objectives such as: minimizing the cost of generated electricity, maximizing microturbine operational efficiency, and reducing environmental emissions. Actual wind and end-use load data were used for simulation studies and the well-established sequential quadratic programming (SQP) optimization technique was used to validate the results obtained from PSO. Promising simulation results indicate the suitability of PSO for real-time energy management of hybrid energy systems.