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1、 Reference number ISO 14954:2005(E) ISO 2005 INTERNATIONAL STANDARD ISO 14954 First edition 2005-02-01 Space systems Dynamic and static analysis Exchange of mathematical models Systmes spatiaux Analyse dynamique et statique change de modles mathmatiques ISO 14954:2005(E) PDF disclaimer This PDF file
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6、opyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2005 All rights reserved ISO 14954:2005(E) ISO 2005 All rights reserved iii Contents Page Forewordiv 1 Scope1 2 Normative references
7、.1 3 Terms, definitions, symbols, and abbreviated terms1 4 General description of models 3 5 General requirements.3 6 Condensation methods5 7 Model delivery checks8 8 Requested outputs10 9 Size limitations10 10 Delivery formats10 -,-,- ISO 14954:2005(E) iv ISO 2005 All rights reserved Foreword ISO (
8、the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical commi
9、ttee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotec
10、hnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the membe
11、r bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifyin
12、g any or all such patent rights. ISO 14954 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 14, Space systems and operations. -,-,- INTERNATIONAL STANDARD ISO 14954:2005(E) ISO 2005 All rights reserved 1 Space systems Dynamic and static analysis Exchange of
13、 mathematical models 1 Scope This International Standard normalizes the exchange of mathematical models between payload contractors (PLC) and launch service providers (LSP). It identifies standard methods for modelling the dynamic behaviour of both launch vehicles (LV) and payload (PL), particularly
14、 when they are coupled prior to launch and during the early moments of the launch phase. In standard mode, the delivered models represent dynamic and static behaviour at the launcher interface. The requirements provided in this International Standard are the minimum necessary for dynamic coupled ana
15、lysis. They may not be sufficient for stress analysis. The payload models are full integrated models from the different parts of the payload under the payload contractor authority, including also their own adapter to LV interface in the case that the adapter is a part of the payload. This Internatio
16、nal Standard does not include the validation of PL models. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (in
17、cluding any amendments) applies. ISO/IEC 646, Information technology ISO 7-bit coded character set for information interchange 3 Terms, definitions, symbols, and abbreviated terms 3.1 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1.1 payload sy
18、stem that is launched by a launch vehicle EXAMPLES Satellite, spacecraft, space probe. 3.1.2 payload contractor organization in charge of a payload 3.1.2 launch service provider organization that conducts a launch with a launch vehicle ISO 14954:2005(E) 2 ISO 2005 All rights reserved 3.2 Abbreviated
19、 terms ATM acceleration transformation matrix CoG centre of gravity DoF degree of freedom DTM displacement transformation matrix EOF end of file ICD interface control document LSP launch service provider LTM load transformation matrix LV launch vehicle OTM output transformation matrix PL payload PLC
20、 payload contractor SI International System of Units 3.3 Symbols A acceleration transformation matrix C damping matrix D displacement transformation matrix K stiffness matrix KR stiffness matrix of rigid body modes, T RRR =KK L load transformation matrix M mass matrix MR mass matrix of rigid body mo
21、des, T RRR =MM Se strain energy qis internal degrees of freedom qj degrees of freedom of the interface R matrix of rigid body modes k modal coordinates ISO 14954:2005(E) ISO 2005 All rights reserved 3 4 General description of models 4.1 Matrices The mathematical model of a PL shall be made of three
22、matrices mass matrix (M), stiffness matrix (K), and damping matrix (C). It shall be sufficient to characterize the dynamic and static behaviour of the structure, assuming that no external forces are applied to the payload except through the LV-PL interface. A modal synthesis method is a typical proc
23、edure used to generate a reduced mathematical model. Additional matrices may be provided in order to reconstitute acceleration, displacement or load in the PL. These matrices are identified as OTMs in the following clauses. 4.2 Types of models 4.2.1 Physical models Physical models shall be represent
24、ed by matrices, the dynamic and static behaviour of which is described solely by the DoFs related to physical displacement at nodal points, including all interface points. 4.2.2 Modal models Modal models shall be represented by matrices, the dynamic and static behaviour of which is described solely
25、by a mix of physical and modal DoFs (representing the modes of the structure fixed at previous physical DoFs). Only interface DoFs are physical DoFs. 4.2.3 Hybrid models Hybrid models are extensions of modal models for which internal physical DoFs other than the interface DoFs are included. 4.3 Unit
26、s All numerical input and output data shall be expressed in SI. Acceleration may be expressed in g, where g = 9,81 m/s2. Use of units other than those of SI is an exception that shall be submitted for the approval of the LSP. 5 General requirements 5.1 Modelling codes The software (name and version)
27、 and the type of finite elements used for the modelling of the PL shall be indicated. The condensation procedure applied to the original dynamic model shall be described. 5.2 Co-ordinate systems A reference co-ordinate system for the PL model shall be defined. A drawing of the PL ensemble with its c
28、o- ordinate system shall be included in the written report. ISO 14954:2005(E) 4 ISO 2005 All rights reserved The orientation of the PL axes with respect to the LV shall be defined by the LSP, based on compliance with requirements of clearance between PL and LV structures, on pad access to the PL, an
29、d on mechanical and electrical interfaces as stipulated in the ICD. The same reference system shall be used for the geometrical description of the PL and for the definition of the DoFs in the mass and stiffness matrices. The axis system shall be cartesian. A local co-ordinate system may be used but
30、shall be clearly defined. For interfaces, all reference shall be made to the reference co-ordinate system. 5.3 Theoretical aspects for modelling 5.3.1 General modelling The model shall describe the complete, dynamic, three-dimensional PL behaviour in free-free conditions and also clamped at its inte
31、rface with the launch vehicle. The model shall be representative up to a frequency specified by the LSP. 5.3.2 Liquid modelling If the payload contains significant liquid propellant mass, the model shall describe the slosh motions of these liquids, neglecting the surface tension and assuming that th
32、e equilibrium surface is perpendicular to the liquids quasi-static net acceleration vector, when required by the LSP. The effects of fluid-structure interaction shall be taken into account in the prescribed frequency range. Typical values of quasi-static acceleration shall be provided by the LSP for
33、 loading cases to be considered. 5.3.3 Damping modelling Damping is usually based on approximations derived from engineering judgement and tests. It may be defined at the PL level, in which case a PL damping matrix shall be a part of the mathematical model. Damping may be defined at the system level
34、 by agreement between PLC and LSP, in which case no damping matrix is required. However, if necessary, the dependence of damping on frequency may be provided. 5.3.4 Interface modelling When the interface between the PL and the LV may be considered rigid, as approved by both the PLC and the LSP, the
35、interface can be condensed to one node with six DoFs. Modelling of the PL-LV interface shall require greater accuracy when the flexibility of the interface might induce higher loads on the PL. This issue shall be discussed by both parties prior to the preliminary coupled analysis cycle. -,-,- ISO 14
36、954:2005(E) ISO 2005 All rights reserved 5 6 Condensation methods 6.1 Condensed physical model 6.1.1 General The choice of method of condensation is left to the discretion of the writer of the model. The condensed model shall be compliant with requirements given in Clause 7. The nodal points and DoF
37、 shall be defined as in 6.1.2. 6.1.2 Requirements 6.1.2.1 Unless otherwise specified, each physical nodal point of the interface shall have six DoFs in the reference co-ordinate system: TX = DoF 1, TY = DoF 2, TZ = DoF 3, RX = DoF 4, RY = DoF 5, RZ = DoF 6 where T is translation, R is rotation and X
38、, Y, Z are the axes. 6.1.2.2 The DoFs shall be ordered in the matrices first according to the numbering of the nodes and second according to the numbering of the DoFs as listed in 6.1.2.1. 6.1.2.3 A local co-ordinate system may be used but shall be defined. In general, local co-ordinates are exclude
39、d for the interface DoFs. 6.1.2.4 Nodal point co-ordinates shall be expressed in the reference system of the PL. 6.1.2.5 As a result of these rules, the mass, stiffness and damping matrices may have a size less than 6N 6N, where N is the number of nodal points. 6.1.2.6 The OTMs may be supplied with
40、related user instructions. The output parameters shall be linearly dependent on the acceleration and/or displacement of nodal points. Thus, the OTMs are likely to have the same number of columns as the stiffness and mass matrices and P rows, where P is the number of output parameters. 6.2 Modal mode
41、l 6.2.1 General The dynamic behaviour of the PL shall be described by the reduced stiffness, mass and damping matrices, relative to the elastic modes (modal co-ordinates, k) and the interface nodes (the interface DoF, qj). This size of the stiffness and mass matrices (and the damping matrix if provi
42、ded) is Q rows Q columns, such that Q = Ql + Qm where: Ql = number of degrees of freedom of the interface Qm = number of elastic modes -,-,- ISO 14954:2005(E) 6 ISO 2005 All rights reserved 6.2.2 Requirements 6.2.2.1 Unless otherwise specified, each physical nodal point of the interface shall have s
43、ix DoFs in the reference co-ordinate system: TX = DoF 1, TY = DoF 2, TZ = DoF 3, RX = DoF 4, RY = DoF 5, RZ = DoF 6 where T is translation, R is rotation and X, Y, Z are the axes. 6.2.2.2 The DoFs shall be ordered in the matrices first according to the numbering of the nodes and second according to
44、the numbering of the DoFs as listed in 6.2.2.1. The modal DoFs shall be numbered differently from the interface nodes because they are considered to have only one degree of freedom. The modal DoFs shall be ordered in the matrices according to the numbering of the modes. 6.2.2.3 Local co-ordinate sys
45、tems may be used but shall be defined. In general, local co-ordinates are excluded for the interface DoFs. 6.2.2.4 Nodal point co-ordinates shall be expressed in the reference system of the PL. 6.2.2.5 The OTMs shall be delivered in order to reconstitute loads, accelerations and displacements of nod
46、es and elements that will allow a verification of the payload design. OTMs shall be separated according to the type of output: k a j q q = A ? ? ? where A is the acceleration transformation matrix (ATM); k d j q q = D where D is the displacement transformation matrix (DTM); kk jj 12 qq =+ FLL ? ? wh
47、ere L1 and L2 are the load transformation matrices (LTM1 and LTM2). The size of these matrices is P rows Q columns, where Q is defined in 6.2.1 and represents the size of the mass or stiffness matrix, and P is the number of output transformation parameters. NOTE P is not necessarily the same for eac
48、h type of matrix. ISO 14954:2005(E) ISO 2005 All rights reserved 7 For the modal model, if a damping matrix is provided it shall be defined as follows: damping relative to interface nodes shall be assumed to be 0, or shall be defined by agreement between LSP and PLC; damping relative to the elastic modes shall be modal damping. 6.3 Hybrid model 6.3.1 General A hybrid model is an extended modal model with more physical DoFs than those solely for the interface. Its use is the same as for the modal model. The dynamic behaviour of the PL