大变形柔性铰链的静刚度分析及应用

大变形柔性铰链可由弹性较大的橡胶材料制成,而橡胶材料的应变-应力关系不符合胡克定律,其关系可由应变-能量函数关系式导出,为此,采用Mooney-Rivlin模型对形变能量函数进行简化,通过适当选取材料常数的比值,对其非线性的应力-应变关系进行分段线性化,导出圆角型柔性铰链在大变形时转角刚度的近似计算公式.通过有限元仿真对近似计算公式进行了验证.在此基础上,应用大变形柔性铰链构造扑翼式微型飞行器中的柔性胸腔,由转动电机作为驱动器,利用柔性铰链的变形实现翅膀的扇翅运动,实际应用效果表明可有效增大扇翅角并提高能量利用率.

Analysis and application of large-deformation flexible hinge

Flexible hinge transfers motion and force by deformation of flexible element, the stiffness of which made by metal material can be calculated on the premise of Hooke’s law. While the stress-strain relation of hyperelastic material is unconformable to Hooke’s law, it must be derived by stress-energy functions. To analysis the stiffness of flexible hinge made by hyperelastic material, a notch flexible hinge was proposed. Approximate formula for stiffness of such hinge was deduced and its scope of application was analyzed. Analysis result comparison between finite element analysis model and approximate formula shows consistency. Flapping flight is ubiquitous in nature and all birds and insects have compliant thoraxes for activating wings to flap. Flexible hinge using in the construction of mechanism offered improvements over rigid hinge on some aspects of large range of motion, long life and saving in power. Application in compliant thorax of micro aero vehicle with flapping wings was realized.