DUT-1非冻结合成模型冰的弯曲强度

Flexural Strength of DUT-1 Synthetic Model Ice

简介了DUT 1非冻结合成模型冰的功能 .给出DUT 1模型冰的弯曲强度的测试装置和设备 .讨论该模型冰在不同加载速度下的破坏方式和发生峰值弯曲强度的条件 .通过悬臂梁上弯和下弯实验结果 ,说明DUT 1模型冰的各向同性 ,检验了浸水模型冰性能的稳定性和模型冰湿密度对峰值弯曲强度的效应 .

The aim and function of the synthetic model ice is described in this paper. In according to the requirement of simulation law of ice interaction with structures, strength and thickness of model ice should follow simulating scale, λ. The statistical values of the Bohai ice feature parameters, such as density, compressive strength, flexural strength, shear strength, elastic modulus and friction coefficient, are available. The ideal physi-cal and mechanical values of the synthetic modelice are determined using the model scale of 1∶10～1∶30, considering the capability of the test basins in China and the natural ice features. A perfect model ice is found and called DUT-1 model ice. Its components and making process are introduced briefly in this paper. Flexural strength is one of the important parameters in the evaluation of interaction between ice and slope structures or waves. Hence, it is one of the simulated parameters in model ice. For knowing the flexural strength of DUT-1 model ice in detail, over 500 samples were tested systematically. It is found that ductile bending happens under a loading rate less than 350～400 kPa·s -1 in simple three point bending and 60～65 kPa·s -1 in cantilever beam bending. Their corresponding failure times are 0.03 ～ 0.38 s and 0.5 ～ 0.76 s, respectively. These failure times are in the range of that of the simulated natural ice. A comparison of flexural strength between downwards and up-wards loading on cantilever beams certifies an anisotropy in the model ice. This is the same with the fine grain frozen model ice, because both are characterized by granular structure. After one hour wetting, the flexural strength of the model ice under three-point is going to be steady and lasts for 4 h. This period is longer enough for performing model test for ice interaction with structure or ice behavior modeling test. Similar with natural ice, the flexural strength of the DUT-1 model ice increases with increasing of wetted density. The flexural strengths both under the three-point bending and the cantilever beam bending are almost the same. In the normal distribution curves of strengths, the scatter is rather large of that under the three-point bending. The flexural strength ranges from 35 to 65 kPa, with a middle value of 45 kPa. The flexural strength of the Bohai natural ice is 450～750 kPa, thus model of 1∶10～1∶30 scale is available.