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Fig. 2 geometric model of the complete main landing gear A geometric model of a complete landing gear shown in Fig. 2 has been used to generate a totally deformable discrete FE model (Figs 3, 4 and 5) to investigate into the dynamics of the landing gear of a transport aircraft. The modelling has been carried out in the MSC.PATRAN environment, the 2005 version, with the LS-Dyna code preferably applied to conduct dynamic analyses. What has been defined for individual solids of the geometric model, which represent particular sections of the landing gear, are the FE meshes, models of materials, and respective types and properties of finite elements that represent the modelled sub- assemblies.

Figure 2 geometric model of the complete main landing gear A geometric model of a complete landing gear shown in Fig. 2 has been used to generate a totally deformable discrete FE model (Figs 3, 4 and 5) to investigate into the dynamics of the landing gear of a transport aircraft. The modelling has been carried out in the MSC.PATRAN environment, the 2005 version, with the LS-Dyna code preferably applied to conduct dynamic analyses. What has been defined for individual solids of the geometric model, which represent particular sections of the landing gear, are the FE meshes, models of materials, and respective types and properties of finite elements that represent the modelled sub- assemblies.

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The influence of a failure on the complete landing gear system are subject of our consideration. Various 3D models of the landing gear part with failure were defined for the static FE analysis. Complete system of the main landing gear was mapped as the deformable 3D numerical model for dynamic analysis with LS-Dyna code. Experimental and numerical research of transport airplane’s landing gear (Fig. 1) are discussed in this paper. Fig. 1 view of the drop stand and the failure of the top landing gear‘s leg
The influence of a failure on the complete landing gear system are subject of our consideration. Various 3D models of the landing gear part with failure were defined for the static FE analysis. Complete system of the main landing gear was mapped as the deformable 3D numerical model for dynamic analysis with LS-Dyna code. Experimental and numerical research of transport airplane’s landing gear (Fig. 1) are discussed in this paper. Fig. 1 view of the drop stand and the failure of the top landing gear‘s leg
fastening it to the strut’s lever, the landing-gear wheel hub, the brake stator and rotor discs, and the tyre (see Figs 2,3,4 and 5). Fig. 3 discrete model with the shock-absorber model included
fastening it to the strut’s lever, the landing-gear wheel hub, the brake stator and rotor discs, and the tyre (see Figs 2,3,4 and 5). Fig. 3 discrete model with the shock-absorber model included
Fig. 5 view of 3D model with the two gaps of fatigue fracture The 3D model described above (see Figs 2,3 and 4) was leveloped for dynamic drop test of complete landing gear. In fact, reflected here in the 3D model particular structural members of the landing gear system keep mating to transmit loads through contacting one another. The mapping of the correct mating of the system’s members in question requires that appropriate regions of contact are mapped in the numerical model. Twelve couples in contact that include surfaces of some structural members of the landing gear have been defined in the model. These are as follows: the wheel hub and the brake stator— two contact areas (Fig. 4), the wheel axle and the bearing races of the wheel hub — three contact areas, the piston rod of the shock absorber and rings and the cylinder sleeve of the lever — four contact areas, the bearing races and pins of the cup-and-ball joint assemblies — two contact areas, and the upper lever of the strut and the fixing sleeve — one contact area.
Fig. 5 view of 3D model with the two gaps of fatigue fracture The 3D model described above (see Figs 2,3 and 4) was leveloped for dynamic drop test of complete landing gear. In fact, reflected here in the 3D model particular structural members of the landing gear system keep mating to transmit loads through contacting one another. The mapping of the correct mating of the system’s members in question requires that appropriate regions of contact are mapped in the numerical model. Twelve couples in contact that include surfaces of some structural members of the landing gear have been defined in the model. These are as follows: the wheel hub and the brake stator— two contact areas (Fig. 4), the wheel axle and the bearing races of the wheel hub — three contact areas, the piston rod of the shock absorber and rings and the cylinder sleeve of the lever — four contact areas, the bearing races and pins of the cup-and-ball joint assemblies — two contact areas, and the upper lever of the strut and the fixing sleeve — one contact area.
Boundary conditions that correspond to those applied in the numerical-test variant under accomplishment were introduced in the landing-gear model. External constraints in the form of fixed pivot bearings were introduced in the nodes that attach the landing gear to the aircraft fuselage structure (i.e. central nodes on side surfaces of the upper pin and the upper-lever sleeve — Fig. 4). What results from numerical tests is a series of data that describe the mating of particular landing-gear structural components in contact areas. It refers to both the kinematics and the dynamics of the structure under consideration. Some selected results of the numerical test showing stress analysis have been shown in Figs 6, 7, 8. Fig. 6 map of maximum principal stresses in the contact area of the shock-absorber’s body (stem) within the node of the pin fastening it
Boundary conditions that correspond to those applied in the numerical-test variant under accomplishment were introduced in the landing-gear model. External constraints in the form of fixed pivot bearings were introduced in the nodes that attach the landing gear to the aircraft fuselage structure (i.e. central nodes on side surfaces of the upper pin and the upper-lever sleeve — Fig. 4). What results from numerical tests is a series of data that describe the mating of particular landing-gear structural components in contact areas. It refers to both the kinematics and the dynamics of the structure under consideration. Some selected results of the numerical test showing stress analysis have been shown in Figs 6, 7, 8. Fig. 6 map of maximum principal stresses in the contact area of the shock-absorber’s body (stem) within the node of the pin fastening it
What has also been included in the paper are analytical esults that illustrate the quality of the numerically epresenting the landing-gear drop under laboratory onditions. Therefore, changes in the shock-absorber’s body isplacement against its cylinder and changes in the vertical esponse recorded on the model of the drop-weight plate have een shown in Figs 9 and 10, respectively. Fig. 9 change in the displacement of the shock-absorber’s body against its cylinder as recorded at the touchdown
What has also been included in the paper are analytical esults that illustrate the quality of the numerically epresenting the landing-gear drop under laboratory onditions. Therefore, changes in the shock-absorber’s body isplacement against its cylinder and changes in the vertical esponse recorded on the model of the drop-weight plate have een shown in Figs 9 and 10, respectively. Fig. 9 change in the displacement of the shock-absorber’s body against its cylinder as recorded at the touchdown
Fig. 13 map of maximum principal stresses in the area of welded joint that connects the upper and lower levers of the main landing gear where the crack gap developed during drop test simulation (see Fig. 1) (o..... = 1470 MPa)
Fig. 13 map of maximum principal stresses in the area of welded joint that connects the upper and lower levers of the main landing gear where the crack gap developed during drop test simulation (see Fig. 1) (o..... = 1470 MPa)
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