3D tolerance modeling and geometric precision analysis of plane features for flexible parts

Int J Adv Manuf Technol

et al. 2022

Self Cite

The measurement and assembly of aeroengine rotor are separated from each other, the uncertainty of the test position leads to the test data cannot reflect the geometric characteristics of the rotor itself, which makes it difficult to accurately measure and predict the assembly accuracy. Combined with the fact that the 2 geometric characteristics of parts / components are not related to the measurement datum, an assembly accuracy test and prediction method is proposed to reduce the datum deviation and ensure the consistency of test data. Firstly, the small displacement torsor is used to describe the datum deviation, the inverse matrix transformation is applied to reduce the datum deviation, and the datum independent matrix is utilized to express the pose characteristics of the parts / components, which provides the data basis for the accurate prediction of assembly accuracy. Then, the pose transfer model based on the datum independent matrix is established, which is more comprehensive and clearer than the traditional accuracy prediction model. Furthermore, a direct optimization method is also established, which is more efficient than the traditional genetic algorithm. The assembly experiment of aeroengine rotor shows that the model and method proposed in this paper are beneficial to reduce the coaxiality of the front and rear fulcrum and they can better reflect the geometric characteristics of the rotor itself. The related research also has reference significance for other large-scale and high-precision mechanical product assembly.

Section: Datum Independent Matrixmentioning

confidence: 99%

Assembly accuracy prediction and optimization of aero-engine rotor under the separation condition of assembly and measurement

Int J Adv Manuf Technol

et al. 2022

Self Cite

“…The processed morphology data cannot be directly used for accuracy analysis, it needs to be fitted to SDT value for subsequent calculation (Mu et al, 2018). The SDT can be expressed as:…”

Section: Derivation Of Monomer Modelmentioning

confidence: 99%

“…Liu et al (2018) considered the loading deformation during assembly process and presented a new tolerance analysis framework based on skin model shapes and a Boundary Element Method for rectangular surface. Mu et al (2018) used the SDT theory to characterize the assembly deformation and established an assembly deviation calculation model based on the Jacobiantorsor model. Sun et al (2019b) considered the geometrical errors and assembly deformation of parts, and then developed a method composed of the matrix theory and finite element analysis (FEA) method to analyze the assembly accuracy of rotating machinery with multi-support structures.…”

Section: Introductionmentioning

confidence: 99%

Monomer model: an integrated characterization method of geometrical deviations for assembly accuracy analysis

Zhao

et al. 2021

Self Cite

Purpose Assembly accuracy is the guarantee of mechanical product performance, and the characterization of the part with geometrical deviations is the basis of assembly accuracy analysis. Design/methodology/approach The existed small displacement torsors (SDT) model cannot fully describe the part with multiple mating surfaces, which increases the difficulty of accuracy analysis. This paper proposed an integrated characterization method for accuracy analysis. By analyzing the internal coupling relationship of the different geometrical deviations in a single part, the Monomer Model was established. Findings The effectiveness of the Monomer Model is verified through an analysis of a simulated rotor assembly analysis, and the corresponding accuracy analysis method based on the model reasonably predicts the assembly deviation of the rotor. Originality/value The Monomer Model realizes the reverse calculation of assembly deformation for the first time, which can be used to identify the weak links that affect the assembly accuracy, thus support the accuracy improvement in the re-assembly stage.

“…Then fitting the data of radial runout and axial runout of the upper and lower assembly surfaces of the rotor based on the least square method to obtain the fitting circle center: ( , ) and fitting plane: + + + = 0. Among them, ( , ) is eccentric coordinates, = − / is the rotation angle of the fitting plane relative to the reference plane around the x axis, and = / is the rotation angle of the fitting plane relative to the reference plane around the y axis, and the rotation direction follows the righthanded spiral rule [34,35].…”

Section: Datum Independent Matrixmentioning

confidence: 99%

Assembly Accuracy Prediction And Optimization of Aeroengine Rotor Under The Separation Condition Of Assembly And Measurement

et al. 2021

Preprint

Self Cite

The measurement and assembly of aeroengine rotor are separated from each other, the uncertainty of the test position leads to the test data cannot reflect the geometric characteristics of the rotor itself, which makes it difficult to accurately measure and predict the assembly accuracy. Combined with the fact that the geometric characteristics of parts / components are not related to the measurement datum, an assembly accuracy test and prediction method is proposed to reduce the datum deviation and ensure the consistency of test data. Firstly, the small displacement torsor is used to describe the datum deviation, the inverse matrix transformation is applied to reduce the datum deviation, and the datum independent matrix is utilized to express the pose characteristics of the parts / components, which provides the data basis for the accurate prediction of assembly accuracy. Then, the pose transfer model based on the datum independent matrix is established, which is more comprehensive and clearer than the traditional accuracy prediction model. Furthermore, a direct optimization method is also established, which is more efficient than the traditional genetic algorithm. The assembly experiment of aeroengine rotor shows that the model and method proposed in this paper are beneficial to reduce the coaxiality of the front and rear fulcrum and they can better reflect the geometric characteristics of the rotor itself. The related research also has reference significance for other large-scale and high-precision mechanical product assembly.