Negative stiffness (NS) mechanical metamaterials have excellent application prospect in a broad range of fields such as energy trapping, repeated energy absorption and so on. Although various kinds of NS mechanical metamaterials have been proposed, one configuration cannot simultaneously achieve multi-stability and mono-stability. This paper presented a novel multifunctional NS mechanical metamaterial structure, which possessed tailored functions of multi-stable and compressive mono-stable state without geometrical parameters adjustment. The novel multifunctional NS mechanical metamaterial structure with a conical shape consisted of both soft and hard material part and was fabricated by additive manufacturing technology. NS behaviors were achieved by the instability of the soft counterpart. Mechanical performance of this novel multifunctional NS mechanical metamaterial structure under axial compression was experimentally and numerically investigated. Influences of geometrical parameters tailoring stable state were systematically investigated and the ratio of offset distance, tilt angle, slenderness were found the key factors. Effective methods to make sure the tri-layer metamaterial structure achieving multi-stable after unloading from completely compacted state were proposed.

负刚度（NS）机械超材料在能量捕获，重复能量吸收等广泛领域中具有极好的应用前景。尽管已经提出了各种NS机械超材料，但是一种构造不能同时实现多稳定性和单稳定性。本文提出了一种新颖的多功能NS机械超材料结构，该结构具有量身定制的功能，可在不调整几何参数的情况下实现多稳态和压缩单稳态状态。新型的具有锥形形状的多功能NS机械超材料结构由软性和硬性材料部分组成，并通过增材制造技术制造。NS行为是通过软副本的不稳定性实现的。实验和数值研究了这种新型的多功能NS机械超材料结构在轴向压缩下的力学性能。系统地研究了几何参数对剪裁稳定状态的影响，确定了偏移距离，倾斜角，细长度的比值是关键因素。提出了有效的方法，以确保三层超材料结构从完全压缩状态卸载后实现多稳态。