地下工程形状记忆合金混凝土“双程梁”特性研究

Research on Properties of a Shape Memory Alloy(SMA) Concrete "Two-Way Beam" Applied in Underground Engineering

文章基于形状记忆合金的双程形状记忆效应,提出了一种新型的智能结构——形状记忆合金混凝土"双程梁";根据力学知识对普通钢筋混凝土梁与形状记忆合金"双程梁"在其抗拉部分的温度高于、低于和等于抗压部分的温度三种情况下的受力性能进行了对比研究,计算分析了形状记忆合金梁在高温环境下被激励后的回复效应,指出了形状记忆合金混凝土"双程梁"在应用推广之前必须解决的问题以及该领域的研究方向。研究结果表明:增加截面尺寸对于改善上下表面温差作用下梁的受力状态不是一个有效的途径;受力机理分析和计算分析一致,合金在相变过程中能对"双程梁"变形产生驱动效应,能主动控制与调整梁的挠度值,能降低温差引起梁产生的弯矩和轴力;此"双程结构"能够提高抗裂能力且适用于地下工程。

Based on the two-way shape memory effect of Shape Memory Alloy （SMA） , an SMA concrete ＂two- way beam＂ is put forward as a new kind of smart structure. Based on mechanical knowledge, the mechanical properties of a reinforced concrete beam and the SMA ＂two-way beam＂ were compared under three conditions （i. e., the temperature of the tensile part being greater than, lesser than and equal to the temperature of the compressive part）. The recovery effect of the SMA beam was analyzed and calculated under a high excitation temperature. Additionally, problems to be solved before the application and promotion of the SMA concrete ＂two- way beam＂ are presented, along with suggested future research in the field. The results show that it is not an effective way to increase sectional dimensions to improve the stress state of a beam with temperature differences between the upper and lower surfaces; the stress mechanism analysis is in agreement with the computational analysis; the SMA has an actuating effect on ＂two-way beam＂ deformation during the phase transformation process and actively controls and adjusts the deflection value of the beam while decreasing the bending moment and axial force of the beam induced by temperature differences. This ＂two-way structure＂ can improve crack resistance and is suitable for underground engineering.