热应力对内含裂隙恐龙化石的影响研究

Study on the Effect of Thermal Stress on Dinosaur Fossils with Inner Crack

摘要:

为深入研究热应力对内含裂隙的恐龙化石的影响，该文模拟10℃,20℃,30℃,40℃,50℃及60℃六种不同温差情形，通过ABAQUS数值模拟软件，揭示地表温度与日照照射在化石表面的温度形成的温差对恐龙化石的影响机制。试验结果表明:在不同温差作用下，热应力的分布主要集中在恐龙化石裂隙的右上角位置，而右下角则没有出现明显的热应力，热应力分布出现不均匀现象，容易诱发恐龙化石开裂，加快风化速度。热应力值随着温差的增大而呈近似线性关系增大。在同一温差、不同轴压条件下，热应力值的增长率呈下降趋势，最大增长率为93.54%，形成于温差为10℃、轴压由0.04MPa变为0.12MPa阶段；热应力值最小增长率为17.46%，形成于温差为60℃、轴压由0.12MPa变为0.20MPa阶段。开裂角随着温差变大而增大，在温差为40℃时，开裂角达51.5°最大值；当温差继续增大时，开裂角呈减小趋势。恐龙化石的极限载荷随着温差的增大而呈下降趋势。其中，温差为10℃时，其极限载荷为最大值2.5MPa，而当温差为60℃时，其极限载荷为最小值1.5MPa。

Abstract:

In order to further study the effect of thermal stress for further research on dinosaur fossils with inner crack, six kinds of temperature difference in 10 ℃,20℃,30℃,40℃,50℃ and 60℃ have been simulated. The mechanism of effect on dinosaur fossils between surface temperature and the inner temperature has been revealed by using ABAQUS numerical simulation software. As showed by the experimental results, under the action of different temperature difference, the distribution of thermal stress is mainly concentrated in the upper right corner of dinosaur fossils crack, while there is no obvious thermal stress in the lower right corner. The distribution of thermal stress is uneven, which is easy to induce the crack of dinosaur fossil and accelerate the weathering speed. The thermal stress increases approximately linearly with the increase of temperature difference. Under the condition of same temperature difference and different axial compression, the growth rate of thermal stress value has the trend of declining.The largest growth rate is 93.54%, which is formed in the temperature of 10 ℃ and axial compression changing from 0.04MPa to 0.12MPa. The minimum growth rate is 17.46%, which is formed in the temperature of 60 ℃ and axial compression changing from 0.12MPa to 0.20MPa. Accompanying with the increase of temperature difference, cracking angle will decrease. When the temperature difference is 40 ℃, the maximum cracking angle is 51.5. When the temperature difference continues to increase, the cracking angle shows a decreasing trend. When the temperature difference grows, the limit load of dinosaur fossil will decrease. Among them, when the temperature difference is 10 ℃, the maximum limit load is 2.5MPa. When the temperature difference is 60 ℃, the minimum limit load is 1.5MPa.