Underwater pressure-resistant structure and variable stiffness fixed connection device, fixed connection method and calculation method thereof

The invention relates to an underwater pressure-resistant structure and a variable-stiffness fixed connection device, fixed connection method and calculation method thereof. The underwater pressure-resistant structure comprises a hydraulic oil cylinder, a cylinder is coaxially arranged on a piston rod of the hydraulic oil cylinder, the top end of the cylinder is movably sleeved with a circular ring connecting piece, and an eight-connecting-rod mechanism is hinged to the bottom end of the circular ring connecting piece and the bottom end of the hydraulic oil cylinder in a crossed mode; the cylinder is sleeved with a spring, and the two ends of the spring make contact with a piston rod of the hydraulic oil cylinder and the circular ring connecting piece respectively. The compression state of the spring can be controlled through the hydraulic oil cylinder, the rigidity is actively adjusted in real time, and the device is suitable for underwater engineering operation. 本发明涉及一种水下耐压结构及其变刚度固连装置、固连方法、计算方法，包括液压油缸，液压油缸的