Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This standard was proposed by the National Medical Products Administration of People’s Republic of China.
This standard is under the jurisdiction of SAC/TC 110/SC 1 the Subcommittee on Orthopaedic Implants of the National Technical Committee on Implants for Surgery and Orthopaedic Devices of Standardization Administration of China.
Standard methods for finite element analysis (FEA) of non-modular metallic orthopaedic hip femoral stems
1 Scope
This standard specifies the requirements and considerations for the numerical simulation for analysis of stresses and strains of non-modular metallic orthopaedic hip femoral stems (that is, only limited to monolithic femoral stems connected with a femoral head through cone) using finite element analysis (FEA) technologies. This standard is only applicable to stresses below the yield strength (provided in the material list).
This standard specifies the requirements and considerations for the development of finite element models to be used in the evaluation of non-modular metallic orthopaedic hip stem designs for the purpose of prediction of the static implant stresses and strains. This standard is applicable to be used for worst case assessment within a series of implant dimensions to promote efficiencies in physical testing to be conducted. This standard recommends the procedures for performing model checks and verification which is helpful to determine if the FEA complies with the requirements in this standard. This standard recommends the content to be included in a simulate engineering mechanics report.
This standard is only applicable to the static structural analysis of non-modular metallic orthopaedic hip stems, excluding the prediction of fatigue strength.
Note: The values stated in SI units are to be regarded as the standard.
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 (including any amendments) applies.
GB/T 31054-2014 Computer aided engineering for mechanical products - Finite element numerical calculation - Terminology
YY/T 0809.4-2018 Implants for surgery - Partial and total hip joint prostheses - Part 4: Determination of endurance properties and performance of stemmed femoral components
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3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 31054-2014 and the following apply.
3.1
finite element analysis; FEA
structural performance analysis based on finite element method
The finite element method (FEM) is a numerical analysis method that discretizes the continuous solution domain into finite elements and uses the approximate solution of finite elements to approximate the real physical system under given constraints.
Note: It is derived from definitions 2.1.2 and 2.1.3 of GB/T 31054-2014.
3.2
node
hinge points between elements Each element only communicates with neighboring elements and the outside at the node.
Note: It is derived from definition 2.1.5 of GB/T 31054-2014.
3.3
boundary conditions
geometric and physical conditions solving on the boundary of the domain under given working conditions
Note: It is derived from definition 2.2.7 of GB/T 31054-2014.
3.4
material property
physical performance parameters of materials, such as modulus of elasticity, Poisson's ratio, density, etc.
Note: It is derived from definition 2.2.8 of GB/T 31054-2014.
4 Significance and use
This standard is applicable to calculate the stresses on the orthopaedic hip femoral stems when loaded according to the method specified in YY/T 0809.4-2018. This method adopted in this standard can be used to determine the worst case dimension for a specific implant.
5 Geometric data
5.1 Finite element models are based on studying geometric characteristics of the implants. The geometric details of implants can be obtained from drawings, solid models, preliminary sketches, or any other source consistent with defining the model geometry. In building the finite element model, certain geometric details may be omitted from the orthopaedic implants shown in the computer aided design (CAD) model if it is determined that they are not relevant to the intended analysis. Engineering evaluation shall be made on the extent of model simplification and it shall be justified.
5.2 For the orthopaedic implant being simulated, it is most appropriate to consider the “worst case” stress condition. The “worst case” shall be determined from all relevant engineering considerations (such as the geometry and dimensions of stem and the femoral head offset). If FEA is being used for determining the worst case, then the femoral head offset in worst case may not be known. It may be necessary to test several variants of the femoral head offset to determine it.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Significance and use
5 Geometric data
6 Material properties
7 Loading
8 Boundary conditions
9 Analysis
10 Report
Bibliography
