Ice, as a novel green and sustainable building material, has attracted more and more attention in building engineering. Appropriate ice material models are crucial for the performance analysis of the increasing ice structures. There is still challenging in modelling ice responses due to the complexity of ice. This study aims to present a nonlinear elastoplastic damage model for ice material. First, a triaxial compression test of artificial ice is conducted. Based on the test results, the modified Tsai-Wu failure criterion with better performance in the tensile zone and physical meaning for hydraulic strength is established. Then, combining plasticity theory with damage mechanics, an elastoplastic damage constitutive law considering the difference between tensile and compressive properties is proposed. The piecewise damage model and the Weibull exponential damage model are employed for compression and tension damage, respectively. Moreover, the numerical iterative algorithm is developed and a user-defined material subroutine (UMAT) is embedded in the finite element software ABAQUS to simulate the mechanical properties of ice. Furthermore, the constitutive model is verified by comparing the FEM results with the results of uniaxial compression, triaxial compression, and three-point bending tests. The results show that the constitutive model can well describe the stress-strain nonlinear behavior and capture the basic failure mode of ice materials. Finally, considering temperature affecting on the failure surface, a temperature dependent ice material model is developed. The current study would help in the design, operation and maintenance of ice structures.

In recent years, interest in the prefabricated ice rink for international competition has increased. The ice sheet, whose support is extruded polystyrene foam board, is prone to bending failure. To maintain the advantage of recycling prefabricated ice rinks, the method of reinforcing ice slabs with welded steel mesh (SRI) was proposed. However, the flexural properties of SRI remain unclear. Therefore, three-point bending tests, theoretical derivation, and finite element analysis were conducted in this study to better understand SRI. First, the three-point bending tests with 17 specimens were performed considering the effects of reinforcement ratio (0%similar to 0.812%). The results showed that the SRI's cracking load capacity and ultimate load capacity improved significantly with 1.84 and 4.49 times higher than the plain ice slab at most. Additionally, reinforcement can reduce the stiffness drop caused by cracking, which can be increased to 0.913 at most. Then, the calculation formula of the cracking load, which is a segmentation function, is derived based plane section assumption and gets good agreement with experimental results. At the same time, the calculation formula of the ultimate load is derived, although the calculation result is conservative, it can reflect the trend of the ultimate load with the variation of reinforcement ratio. Finally, finite element simulation analysis of three-point bending tests of SRI were conducted, using the brittle cracking model and the Coulomb-Moore plasticity model, respectively. Simulation results show that using both models alone have the limitation of use range. As a result, a B + C combined numerical model (the brittle cracking model is used for the tension zone and the Coulomb-Mohr plasticity model is used for the compressive zone) was proposed, and the simulation results agree well with the cracking load of both experiment and formula. Taken together, the welded steel mesh effectively improves the flexural performance of ice slabs and the findings of this study are beneficial for the design and finite element analysis of SRI in the future.

During curling sports, the movement of the stone is affected by the quality of the ice. Therefore, the delivery team led by the ice maker hopes that the quality of the ice surface will be stable and that the athletes will always ‘read the ice’ and pay attention to the small changes in the ice surface. This phenomenon is the charm of curling. Many friction models have been proposed to describe the regularity of the curling motion. In the curling competitions of the 2022 Beijing Winter Olympic Games, the 2021 World Wheelchair Curling Championships, and the warm-up competition before, the research team installed a video image capture system in the arena to capture and record the data of the curling motion by using the depth neural network and object tracking algorithm. Further motion data research verifies the relationship between the friction coefficient and the speed. The quality control parameter of ice rink α is proposed, which is related to the influencing factors of the ice surface temperature, the ice hardness, the size of the pebble point, and the width of the curling friction band. The quality of the curling ice rink can be evaluated accurately and comprehensively by using parameter α. Based on the relationship between the friction coefficient and the speed, a physical model of horizontal sliding of the curling stone is established, which agrees well with the results of data obtained from video acquisition. Therefore, the movement distance along the rink can be accurately predicted. This paper analyzes the relationship between the long-time (the time it takes for the curling stone to travel between the two hog lines) and the stop position and that between the long-time and the split-time (the time it takes for the curling stone to travel from the back line to the hog line). Based on this result, a ruler can be established to assist athletes in estimating the sliding distance of the stone before curling throwing. This research also studies the relationship between three factors (the sliding speed in the x-direction, the angular speed, and a tiny lateral deflection speed in the y-direction) and the deviation of the stone. At the same time, there are also some interesting phenomena of the lateral deflection of the stone, such as the relationship between the lateral deflection angle tanθ and the initial lateral speed. As a result, the prediction of the curling stone’s exact final location can be realized. In summary, this article proposes an indicator for evaluating the quality of ice rinks and a physical model of curling based on the curling friction model, which is validated by data obtained from a video capture system of the 2022 Beijing Winter Olympics. The results described above have been applied in the post-match operation of the National Aquatics Center to guide the production of Olympic-grade ice surfaces and to guide athletes to “read ice” accurately during training.

In the curling sport, the coefficient of friction between the curling stone and pebbled ice is crucial to predict the motion trajectory. However, the theoretical and experimental investigations on stone–ice friction are limited, mainly due to the limitations of the field measurement techniques and the inadequacy of the experimental data from professional curling rinks. In this paper, on-site measurement of the stone–ice friction coefficient in a prefabricated ice rink for the Beijing Winter Olympics curling event was carried out based on computer vision technology. Firstly, a procedure to determine the location of the curling stone was proposed using YOLO-V3 (You Only Look Once, Version 3) deep neural networks and the CSRT Object tracking algorithm. Video data was recorded during the curling stone throwing experiments, and the friction coefficient was extracted. Furthermore, the influence of the sliding velocity on the friction coefficient was discussed. Comparison with published experimental data and models and verification of the obtained results, using a sensor-based method, were conducted. Results show that the coefficient of friction (ranging from 0.006 to 0.016) decreased with increasing sliding velocity, due to the presence of a liquid-like layer. Our obtained results were consistent with the literature data and the friction model of Lozowski. In addition, the experimental results of the computer vision technique method and the accelerometer sensor method showed remarkable agreement, supporting the accuracy and reliability of our proposed measurement procedure based on deep learning.

Interest in the construction of prefabricated ice rink for international competition has increased in recent years, where the ice sheet is directly supported by soft thermal insulation materials. However, bending failure in the ice sheets for these rinks is highly possible because of different compression and tension behaviors. Moreover, the mechanical behaviors of the artificial ice produced layer-by-layer in rinks remain unclear. Therefore, microstructure observations, hardness tests, and three-point bending tests were conducted in this study to better understand artificial ice. First, the crystal structures were obtained through observations in both the vertical and horizontal directions. Then, the hardness of the ice surface at different temperatures, water qualities, ice-making methods, and surrounding environmental conditions was measured using the Shore hardness apparatus. Finally, systematic three-point bending tests on 80 effective ice specimens under a wide range of loading and ice-making parameters were performed. The results show that artificial ice is a typical kind of columnar ice with smaller grain sizes at lower surfaces. The ice surface hardness, roughly normally distributed, was mainly affected by temperature and ice-making mode. Moreover, it was found that all the test ice beam exhibited brittle fracture, and the flexural strength ranged from 0.84 to 2.47 MPa, with the maximum average at a strain rate of 1 × 10–4 s–1. Based on these test results, empirical functions for the effects of the investigated parameters on the flexural strength and effective modulus were developed. Also, the relationships between flexural and tensile strength for artificial ice were established using Weibull law and the coupled criterion. In addition, the linear regression model was established and verified using different prediction methods to predict the ice flexural behavior in practical rinks based on the measured hardness in a simple, reliable, and nondestructive way. The current experiment and analysis are beneficial for the design, operation and maintenance of prefabricated ice rinks.

Interest in ice engineering has increased in recent years, from predicting the ice load during the complex process of ice-structure interaction in the structural design analysis and optimization of ships and marine structures, to calculating the load-carrying capacity of ice as a building structure. Appropriate yield and failure criteria are crucial to the successful prediction of ice failure process. However, few papers systematically present a literature overview of the developed criteria. To better understand ice behavior under these scenarios, it is essential to make a comprehensive survey on the existing yield or failure criteria used for ice material before a criterion is proposed, modified or employed in ice engineering. In this survey, the theories behind various criteria, experimental verifications with ice specimens under multiaxial loading and engineering applications in ice-structure interaction scenarios were first performed. In addition, comparisons of the above-mentioned criteria according to the key influencing factors of ice behavior, as well as some recommendations for the future research were presented. Based on the survey, it was found that most criteria overestimated ice strength under high hydrostatic pressure, not suitable to account for the phenomenon of strength decrease due to pressure melting. However, in some conditions with low or moderate confining pressure, e.g., in bending failure, they have good performance in predicting ice response. In numerical analysis on ice-ship and ice-offshore structure collision scenarios, Crushable foam and Tsai–Wu yield criteria are mostly employed to simulate the ice behavior with the relevant reliability and accuracy. Moreover, in recent studies, it shows better potential for adopting the yield criteria of well-researched concrete material to simulate ice characteristic. Additionally, further studies on post-yielding behavior, combination of yield theory and damage mechanics, multiscale evaluation on existing ice criteria in different application scenarios and applying Hsieh–Ting–Chen and Bresler–Pister criteria driven from concrete material were suggested.

人与结构相互动力作用可以将人的动力特性与结构动力特性耦合,并使耦合体系产生新的动力特性,已成为柔性结构人致振动以及舒适度研究中的一个重要领域.针对人与结构相互作用模型以及相互影响机理,国内外学者开展了一系列试验研究和理论分析.本文首先介绍了相互作用荷载的测量和建模方法,然后针对相互作用人体动力模型、人与结构相互影响的研究进展进行阐述.已有的研究结果表明,人作为重阻尼动力系统能够增加结构阻尼,改变结构频率;结构振动能够影响人的运动方式,从而改变人致荷载,同时,不同幅值、频率的振动使人体动力参数在一定范围内变化.最后,从人致荷载测量、人与结构相互作用耦合系统和结构振动对人的影响3个方面展望了人与结构相互作用的研究方向.

The construction of a prefabricated ice rink has recently attracted considerable interest owing to its detachability, short building period, and high cooling efficiency, among other benefits. Characterizing the compressive properties of an artificial ice sheet is crucial in the design, operation, and maintenance stages of the rink. Several uniaxial compressive tests were conducted in the present work to better understand the mechanical behavior of artificial ice in winter sports rinks. The artificial ice was produced using homemade equipment to simulate the real ice-making conditions in the rink. Comprehensive conditions such as strain rate, ice temperature, ice-making method, water quality, air temperature and humidity were considered in the experiments. The obtained results show that the compressive behavior of artificial ice is considerably affected by the strain rate and ice temperature, and slightly affected by the ice-making method and water quality, whereas the effects of air temperature and humidity are inconclusive. The identified range of strain rate for ductile-brittle transition was within 8.3 × 10−5 s–1 and 8.3 × 10−4 s−1, in which the strength reaches a maximum value at 1.7 × 10–4 s−1. The influencing factors on the compressive strength and effective modulus were analyzed based on the experimental observations, and fitting functions were established to describe the relationships. The results of this study will hopefully provide a reference for the design and optimization of ice rinks, particularly for prefabricated rinks.

A novel prefabricated curling rink supported by steel frame and precast concrete blocks has been tested by the 2019 China Youth Curling Open, and that will be responsible for the Beijing Winter Olympics and Winter Paralympics curling competitions in 2022. Due to quite limited researches on the mechanical properties of this professional curling venue, the dynamic behavior of the prefabricated rink under human activities are not well understood. In particular, people and curling stones are potentially more susceptible to the ice vibrations when compared to the traditional curling rink constructed on rammed foundation. Small ice rink vibrations caused by the human locomotion load can make athletes feel uncomfortable, which could affect competition experience, techniques, and skills of the occupancies. At the same time, it can also result in a slightly change of the curling stone trajectories, which ultimately caused the athletes to adopt an erroneous strategy. In order to get a further understanding of the above problems, this paper conducts a series of performance studies based on the 3D finite element model built in ABAQUS and the measured dynamic loads. In this context, it includes the research of on-site measurement of dynamic loads caused by different types of human locomotion on ice sheet, which can provide a reference to the dynamic performance design of prefabricated curling rink supported by similar structural systems. Moreover, the time and amplitude parameters of the footfall forces are extracted to analyze and be compared with the human induced loads results from the existing research, generally obtained on the concrete surface. Then, on the base of the finite element model verified by experiment, the experimental achieved loads are applied for the dynamic analysis to study the vibration acceleration and velocity response of ice sheet. Finally, the vibration response results, including peak acceleration (PA), vibration dose value (VDV), root mean square acceleration (RMS), as well as root mean square velocity were evaluated according to the regulations proposed by the International Olympic Committee and the vibration evaluation standards suggested by AISC design guide, ISO guideline, and VC curves. The analysis results indicate that innovation prefabricated curling ice rink supported by steel-concrete composite floors can meet the requirements of the event and has the prospect of promotion and application.

On the basis of not destroying the original function, the non-curling field is transformed into a new curling ice rink that meets certain professional requirements through the detachable and prefabricated structure. This curling ice rink is an innovative type of prefabricated curling rink compared with the traditional rink, which has excellent advantages in terms of functional transformation and refrigerating efficiency. However, due to the vibration of the supporting structure and the deformation of the insulation foam under the ice layer, the annoying vibration and ice surface cracking are easy to occur. The static and dynamic performance of the new type of prefabricated curling ice rink located in Beijing, China, in the National Aquatics Center (Water Cube) was analyzed by a series of in situ tests. The field test consisted of two phases: the steel-framed concrete slab prefabricated structure test before ice making and the curling ice rink test after ice making. Phase 1 consisted of graded static load test and dynamic characteristic test as well as analytical frequency predictions. Phase 2 included static load test and dynamic test, long-term vertical deformation at the center point of column grid region on the precast concrete slabs for 19 days, and horizontal deformation at key points of the curling rink during 2019 China Junior Curling Open. A 3D finite element model was established using ABAQUS software, and the natural frequency and key deformation values obtained by modeling were compared with the corresponding ones from experiments. According to the proposed evaluation criteria, the results show that the mechanical properties and deformation ability of this new type of functional transformation curling rink are suitable for application in large international competitions.