Quasi-zero-stiffness (QZS) is beneficial to achieving wider vibration isolation band. However, existing QZS isolators are usually configured with negative stiffness and linear spring, and can only achieve QZS under a specific load, which greatly limits their application in many scenarios. Here, we proposed a magnetically modulated tetrahedral structure (MMTS) that can achieve QZS under different loads. The MMTS is mainly composed of two parts: the tetrahedral structure and a pair of repulsive magnets. Static analysis shows that although the tetrahedral structure consists of simple basic mechanical elements (rods, sliders, and linear springs), it can provide flexible and adjustable negative stiffness. And this negative stiffness can be modulated by the hardening stiffness of the repulsive magnets to realize QZS. The method of realizing QZS by modulating negative stiffness with hardening stiffness is essentially different from the traditional method (connecting linear spring and negative stiffness mechanism). More importantly, no matter how the negative stiffness is adjusted, effective modulation can be achieved by setting appropriate magnet spacing. As a result, QZS can be obtained under different loads. A dynamic model is developed to characterize the dynamic behavior of the system, and the displacement transmissibility is derived using the harmonic balance method (HBM). Comprehensive parameter analysis is conducted to explore its vibration isolation performance. An experimental prototype is manufactured and tested to verify the theoretical model and analysis. Experimental results illustrated that the MMTS can effectively suppress the frequency components above 4 Hz under different external excitations. This novel MMTS provides a new idea to realize QZS under different loads and has great potential for engineering practice.

准零刚度（QZS）有利于实现更宽的隔振带。然而，现有的QZS隔振器通常配置负刚度和线性弹簧，只能在特定载荷下实现QZS，极大地限制了其在许多场景中的应用。在这里，我们提出了一种可以在不同负载下实现 QZS 的磁调制四面体结构 (MMTS)。MMTS主要由两部分组成：四面体结构和一对排斥磁体。静力分析表明，虽然四面体结构由简单的基本机械元件（杆、滑块和线性弹簧）组成，但它可以提供灵活可调的负刚度。并且这种负刚度可以通过排斥磁体的硬化刚度来调制以实现QZS。通过硬化刚度调制负刚度实现QZS的方法与传统方法（连接线性弹簧和负刚度机构）有本质区别。更重要的是，无论负刚度如何调整，都可以通过设置合适的磁体间距来实现有效调制。因此，可以在不同负载下获得 QZS。开发了一个动态模型来表征系统的动态行为，并使用谐波平衡法 (HBM) 推导出位移传递率。进行综合参数分析，探讨其隔振性能。制造并测试了实验样机以验证理论模型和分析。实验结果表明，在不同的外部激励下，MMTS 可以有效地抑制 4 Hz 以上的频率分量。这种新颖的MMTS为实现不同负载下的QZS提供了一种新思路，具有很大的工程实践潜力。