Multibody Analysis Guide ANSYS phần 3

Một yếu tố chung là thường được định nghĩa bằng cách xác định hai nút, I và J. Các nút này có thể được tự ý đặt trong không gian. Có những trường hợp, tuy nhiên, khi một trong các nút cần được xem xét như là một nút "căn cứ". Trong trường hợp này, chỉ định | Chapter 2 Modeling in a Multibody Simulation Revolute Joint Constrained degrees of freedom UX UY UZ ROTX ROTY Universal Joint Constrained degrees of freedom UX UY UZ ROTY Slot Joint Constrained degrees of freedom UY UZ Translational Joint Constrained degrees of freedom UY UZ ROTX ROTY ROTZ Cylindrical Joint Constrained degrees of freedom UX UY ROTX ROTY Release - 2009SAS IP Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS Inc. and its subsidiaries and affiliates. 16 . Joint Element Types Spherical Joint Constrained degrees of freedom UX UY UZ Planar Joint Constrained degrees of freedom UZ ROTX ROTY . Joint Element Connectivity Definition A joint element is typically defined by specifying two nodes I and J. These nodes may be arbitrarily located in space. There are instances however when one of the nodes needs to be considered as a grounded node. In such cases specify either node I or node J appropriately. In cases when the node is grounded the location of the grounded node is taken to be that of the other specified node. Example If the first node of the joint element is a grounded node then the element definition is E J or EN Element-Number J Similarly if the second node is the grounded node then the element definition is E I or EN ElementNumber I Release - 2009SAS IP Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS Inc. and its subsidiaries and affiliates. 17 Chapter 2 Modeling in a Multibody Simulation . Joint Element Section Definition Each joint element must have an associated section definition. Use the SECTYPE command to define the section type and subtype. Example The universal joint section definition is SECTYPE JOINT UNIV UNIV-01 . Local Coordinate System Specification for Joint Elements Local coordinate systems at the nodes are required to define the kinematic constraints of a joint element. Use the SECJOINT command to do so. The local .