Analysis of landing contact force of landing gear footpad based on ABAQUS
SUN Ziqiang
XU Wei
YAN Ming
JIN Yingli
Abstract：[Objective]With the increasing demands for flight safety of unmanned aerial vehicles(UAVs),the dynamic characteristics of landing gear systems have become a critical research focus in UAV design.This study focuses on the landing contact mechanical behavior of rubber footpads in six-link landing gears and investigates the problems of nonlinear mechanical characteristics in modeling.By constructing a precise dynamic contact model,this research aims to elucidate the mechanical response mechanisms of rubber buffers under impact loads and provide theoretical support for optimizing the structural design of cushioning systems at landing gear foot ends.[Methods]A nonlinear contact mechanics model for rubber materials was developed based on the theoretical framework of the continuous contact force method.Innovatively integrating Hertzian contact theory with the Mooney-Rivlin strain energy function,the model accurately characterized the hyperelastic characteristic of rubber materials and the dynamic coupling effects at contact interfaces through non-ideal elastic collision relationships.On the ABAQUS platform,a finite element model adopting the Mooney-Rivlin hyperelastic constitutive model was established,and the landing collision process was numerically simulated using an implicit dynamic solver.A drop impact test bench equipped with force sensors was constructed to obtain experimental data for model validation.This integrated methodology,combining theoretical modeling,numerical simulation,and experimental validation,effectively overcomes the limitations of traditional empirical formulas.[Results]Systematic analysis reveals the influence of multiple physical parameters on contact mechanical characteristics.When the drop height increases within the range of 50 mm to 200 mm,the peak contact force exhibits proportional growth,with an increment of 1.78 kN.Within the load mass range of 5 kg to 20 kg,the peak contact force demonstrates an approximately linear relationship with load mass,showing an increase of 1.02 kN.Notably,increasing footpad thickness has an insignificant effect on reduction in impact force,while optimizing the footpad shape can effectively mitigate impact-induced vibrations.Comparative studies on structural shapes demonstrate that conical footpads,compared to traditional cylindrical designs,exhibit more even force distribution and effectively mitigate impact-induced vibrations.Experimental validation confirms the effectiveness of the model,with the peak contact force error being merely 6％and a phase shift of key parameters controlled within 3 ms under the condition of 100 mm drop height.[Conclusion]The contact force demonstrates approximately directly proportional relationships with both drop height and footpad thickness,though the effect of thickness is relatively weak.Footpad shape optimization significantly reduces impact-induced vibrations,with conical footpads exhibiting superior cushioning performance.This study achieves theoretical breakthroughs in two aspects.A dynamic contact prediction method for rubber buffers was proposed by combining the continuous contact force method with the hyperelastic constitutive model,resolving the technical bottleneck of traditional approaches in addressing nonlinear coupling effects.A quantitative evaluation framework for cushioning performance was established by investigating the influence of multiple physical parameters on contact force at landing gear foot ends,providing a reliable theoretical basis for foot-end parameter optimization.
Keywords：rubber footpadlanding collisioncontinuous contact force methodelastic contactmechanical modelfinite element softwarecontact force analysisenergy absorbing buffer
Publication Date：2025-07-25
Online Publishing Date：2025-09-18(First online date of this platform, not the publication date of the document)
Pages：7( 517-523 )