We study a new class of elliptic variational-hemivariational inequalities arising in the modelling of contact problems for elastic ideally locking materials. The contact is described by the Signorini unilateral contac...We study a new class of elliptic variational-hemivariational inequalities arising in the modelling of contact problems for elastic ideally locking materials. The contact is described by the Signorini unilateral contact condition and the friction is modelled by the nonmonotone multivalued subdifferential condition which depends on the slip. The problem is governed by a nonlinear elasticity operator, the subdifferential of the indicator function of a convex set which describes the locking constraints and a nonconvex locally Lipschitz friction potential. The result on existence and uniqueness of solution to the inequality is shown. The proof is based on a surjectivity result for maximal monotone and pseudomonotone operators combined with the application of the Banach contraction principle.展开更多
针对运载火箭共底贮箱独特的密封锁底焊缝承压结构开展搅拌摩擦焊工艺技术研究,采用基于锁底结构搅拌工具设计的无匙孔回抽全焊透工艺技术,探究搅拌针长度、前进侧位置、坡口尺寸对4 mm 2A14铝合金锁底焊缝强度的影响。经过焊接试验验证...针对运载火箭共底贮箱独特的密封锁底焊缝承压结构开展搅拌摩擦焊工艺技术研究,采用基于锁底结构搅拌工具设计的无匙孔回抽全焊透工艺技术,探究搅拌针长度、前进侧位置、坡口尺寸对4 mm 2A14铝合金锁底焊缝强度的影响。经过焊接试验验证,针长度为-0.1~0.3 mm,前进侧位于锁底侧,焊接坡口设为0.5mm时为最优焊接工艺参数,焊缝强度高于熔焊焊缝强度。对锁底焊缝引钩(HOOK)缺陷进行研究,抑制了HOOK的产生,实现了搅拌摩擦焊方法在运载火箭承压锁底结构的首次应用与飞行验证,提高了焊接效率和质量,并实现整箱减重。展开更多
超越弹簧离合器可用于高速直升机传动系统,具有简单、可靠、质轻的特点。离合器依靠弹簧和输入、输出壳体的摩擦来传递扭矩,在正向传递动力过程中要满足的自锁条件下,分析了超越弹簧离合器接触条件下的最小摩擦系数,同时研究了弹簧离合...超越弹簧离合器可用于高速直升机传动系统,具有简单、可靠、质轻的特点。离合器依靠弹簧和输入、输出壳体的摩擦来传递扭矩,在正向传递动力过程中要满足的自锁条件下,分析了超越弹簧离合器接触条件下的最小摩擦系数,同时研究了弹簧离合器用材料4Cr5Mo Si V钢的摩擦系数随表面粗糙度的变化规律,结果表明摩擦系数随着表面粗糙度的增加,先减小后增大,Ra存在一最佳值,在此Ra值下,摩擦系数最小;由于在反向超越过程中,磨损是超越离合器一直存在的问题,基于Archard磨损计算模型,利用组合磨损计算方法,得出了超越弹簧离合器的磨损寿命。展开更多
基金supported by the National Science Center of Poland under the Maestro 3 Project No.DEC-2012/06/A/ST1/00262the project Polonium“Mathematical and Numerical Analysis for Contact Problems with Friction”2014/15 between the Jagiellonian University and Universitde Perpignan Via Domitia
文摘We study a new class of elliptic variational-hemivariational inequalities arising in the modelling of contact problems for elastic ideally locking materials. The contact is described by the Signorini unilateral contact condition and the friction is modelled by the nonmonotone multivalued subdifferential condition which depends on the slip. The problem is governed by a nonlinear elasticity operator, the subdifferential of the indicator function of a convex set which describes the locking constraints and a nonconvex locally Lipschitz friction potential. The result on existence and uniqueness of solution to the inequality is shown. The proof is based on a surjectivity result for maximal monotone and pseudomonotone operators combined with the application of the Banach contraction principle.
文摘针对运载火箭共底贮箱独特的密封锁底焊缝承压结构开展搅拌摩擦焊工艺技术研究,采用基于锁底结构搅拌工具设计的无匙孔回抽全焊透工艺技术,探究搅拌针长度、前进侧位置、坡口尺寸对4 mm 2A14铝合金锁底焊缝强度的影响。经过焊接试验验证,针长度为-0.1~0.3 mm,前进侧位于锁底侧,焊接坡口设为0.5mm时为最优焊接工艺参数,焊缝强度高于熔焊焊缝强度。对锁底焊缝引钩(HOOK)缺陷进行研究,抑制了HOOK的产生,实现了搅拌摩擦焊方法在运载火箭承压锁底结构的首次应用与飞行验证,提高了焊接效率和质量,并实现整箱减重。
文摘超越弹簧离合器可用于高速直升机传动系统,具有简单、可靠、质轻的特点。离合器依靠弹簧和输入、输出壳体的摩擦来传递扭矩,在正向传递动力过程中要满足的自锁条件下,分析了超越弹簧离合器接触条件下的最小摩擦系数,同时研究了弹簧离合器用材料4Cr5Mo Si V钢的摩擦系数随表面粗糙度的变化规律,结果表明摩擦系数随着表面粗糙度的增加,先减小后增大,Ra存在一最佳值,在此Ra值下,摩擦系数最小;由于在反向超越过程中,磨损是超越离合器一直存在的问题,基于Archard磨损计算模型,利用组合磨损计算方法,得出了超越弹簧离合器的磨损寿命。
