Modeling and Control of a Hybrid Passive/Semi-Active Magnetorheological Recoil Damper with a Pressure-Actuated Stroke-Limiting Valve

This study presents analytical modeling and numerical simulation of a double-adjustable magnetorheological (MR) recoil damper combining a field-controlled inner valve, an effectively field-free bypass, and a pressure-actuated lid. A quasi-steady hydraulic model coupled to lid dynamics describes lock-up, open-lid, and closed-lid states. For the baseline geometry and a prescribed yield stress of 40 kPa, the dynamic force range is approximately three to four below passive closure. After seating, nearly all flow passes through the bypass, and field control becomes negligible. Under the nominal firing pulse of a 20 mm cartridge, constant-field operation gives the shortest predicted stroke and lowest counter-recoil velocity among the three double-adjustable operating modes, with a transmitted-force peak close to the conventional-spring value. Velocity-triggered on–off operation retains most of the rebound reduction while applying the field only during counter-recoil; relative to the spring, it reduces stroke by nearly 40% and battery-stop kinetic energy by about 91%. Two fixed linear viscous dampers provide soft and hard reference levels, and the hard reference closely reproduces the constant-field response over the examined load-amplitude range. At reduced loads below passive lid seating, on–off operation lowers the transmitted-force peak relative to the 40 kPa constant-field case at the cost of a longer stroke; this trade-off does not establish superiority over lower constant-field settings. These results describe conditional performance trade-offs; the early closure transient and the coupled device response remain experimentally unvalidated.