Modeling and simulation of a quarter car model with a nonlinear damper

An empirical investigation of a simple passenger quarter car model is presented. A differential equation of a quarter car model is carried out using MATLAB. Experiments are performed on a passive damper suspension to obtain the characteristics of a nonlinear damper, namely, the backbone of Force versus Velocity curves in which describes nonlinear effects that depend on varying frequencies and amplitudes of the road profile. The backbone is used to find the polynomial equations up to the order of 4 are applied. Results using the experimental parameters and the simulation models are obtained so that comparisons with respect to the performance of the damper are made. A road profile is then used to simulate a quarter car models using these nonlinear equations. Analysis of the results includes position, velocity, and acceleration of the sprung and unsprung masses of the model in a range of frequencies with respect to the input road profile

Numerical Modelling of Bird Strike on Aerospace Structures by means of Coupling FE-SPH

This article offers a parametric mechanics investigation in defining the correlation between the parameters of a wing-body during a bird strike collision. A commercial software of LS-Dyna is used to compute the numerical modelling manifested in this research. In this study, it is an attempt to form a definitive work based on the Smoothed Particle Hydrodynamics (SPH) formulation by recognising the most critical influencing parameters in the bird-strike computation and verify the simulation with the experiment data. For instance, an idealised bird is modelled as a cylindrical shape with hemispherical ends to maintain the homogeneity and symmetry using SPH approach. Moreover, an aluminium alloy rigid flat plate is modelled as a shell element plate in the finite element model (FEM). Here, internal energy vs time for different plate thickness graph are plotted to observe the difference of absorbed energy during the impact. Such conditions are considered in this research from the sight of bird strike impact under multiple states (structural thickness) and constraints (bird size). The obtained computational results are in adjacent agreement with the experimental results published in another literature

Computational modelling of bird strike impact on an aluminium alloy plate via coupling of FE-SPH

This paper proposes a parametric mechanics study in determining the relationship between the parameters of the aerospace structure during a bird strike impact. A commercial software of LS-Dyna is used to compute the numerical modelling demonstrated in this research. Technically, an idealised bird is modelled as a cylindrical shape with hemispherical ends to maintain the homogeneity and symmetry using Smoothed Particle Hydrodynamics (SPH) approach. At the same time, an aluminium alloy plate is developed as a shell element plate in the finite element model. Such conditions are considered in this research from the view of bird strike impact under various conditions (structural thickness) and constraints (bird size). The obtained computational results are in close agreement with the experimental results published in another literature

Numerical modelling of bird strike on a rotating engine blades based on variations of porosity density

A numerical investigation is conducted on a rotating engine blade subjected to a bird strike impact. The bird strike is numerically modelled as a cylindrical gelatine with hemispherical ends to simulate impact on a rotating engine blade. Numerical modelling of a rotating engine blade has shown that bird strikes can severely damage an engine blade, especially as the engine blade rotates, as the rotation causes initial stresses on the root of the engine blade. This paper presents a numerical modelling of the engine blades subjected to bird strike with porosity implemented on the engine blades to investigate further damage assessment due to this porosity effect. As porosity influences the decibel levels on a propeller blade or engine blade, the damage due to bird strikes can investigate the compromise this effect has on the structural integrity of the engine blades. This paper utilizes a bird strike simulation through an LS-Dyna Pre-post software. The numerical constitutive relations are keyed into the keyword manager where the bird’s SPH density, a 10 ms simulation time, and bird velocity of 100 m/s are all set. The blade rotates counter-clockwise at 200 rad/s with a tetrahedron mesh. The porous regions or voids along the blade are featured as 5 mm diameter voids, each spaced 5 mm apart. The bird is modelled as an Elastic-Plastic-Hydrodynamic material model to analyze the bird’s fluid behavior through a polynomial equation of state. To simulate the fluid structure interaction, the blade is modelled with Johnson-Cook Material model parameters of aluminium where the damage of the impact can be observed. The observations presented are compared to previous study of a bird strike impact on non-porous engine blades

Ride quality comparison of a quarter car model with a nonlinear hydraulic damper and an andre hartford friction damper

The paper discusses the ride quality of two different quarter car models. Attached to the first model is a nonlinear passive hydraulic damper while the second model is equiped with an Andre Hartford friction damper. Both of the dampers are physically tested and their characteristics are obtained by using a damper test rig. Based on the force-velocity curves of the dampers polynomial models are developed through the implementation of Lavenberg-Marquadt algorithm. Once the coefficients of the polynomials for both dampers are obtained the equations are plugged into the quarter car model and by using Scilab the response of the system are simulated using a 4th order Runge-Kutta algorithm. The disturbance to the system is assumed of having a step and a sinusoidal inputs. Based on these disturbances the vertical displacements and vertical accelerations of the sprung mass for both systems are analyzed. From the results obtained the ride quality of both systems are determined by the magnitudes of the accelerations and the settling time of the sprung mass. The smaller the acceleration and the faster the system settles indicate that the ride quality of the system is better than the other

Numerical Modelling of Bird Strike on a Rotating Engine Blade Based on Variations of Porosity Density

A numerical investigation is conducted on a rotating engine blade subjected to a bird strike impact. The bird strike is numerically modelled as a cylindrical gelatine with hemispherical ends to simulate impact on a rotating engine blade. Numerical modelling of a rotating engine blades has shown that bird strikes can severely damage an engine blade especially as the engine blade rotates as the rotation causes initial stresses on the root of the engine blade. This paper presents a numerical modelling of the engine blades subjected to bird strike with porosity changes implemented on the engine blades to investigate further damage assessment due to this porosity effect. As porosity has an effect on the decibel levels on a propeller blade or engine blade, the damage due to bird strikes can investigate the compromise this effect has on the structural integrity of the engine blades. The data is presented through variations of bird strike impact velocity and engine blade rotation as a function of porosity

Numerical investigation on the damage of whirling engine blades subjected to bird strike impact

This research renders a numerical investigation of whirling engine blades subjected to bird strike impact. The numerical modelling of the bird strike investigation was conducted employing SPH. The bird model was established as a gelatine material and is the geometry of the bird was anticipated. As most bird strikes transpire during take-off and landing, the bird was modelled with a set velocity of 120m/s and is impacted on the engine blades, where the damage of the blades is then assessed. The engine blades were modelled as a tetrahedron mesh for accuracy in LS-DYNA software and are rotating at 200 rad/s counter-clockwise. The engine blade material is modelled with Johnson-Cook failure constants. The results are manifested as effective stresses, which shows the structural damage of the engine blades struck by the bird, which induces deflection that significantly damages the blades. Further assessments of bird velocity and engine blade rotation variations are also presented

Damage assessment on numerical modelling of rotating engine blades subjected to bird strike

This paper presents a numerical modelling of rotating engine blades subjected to bird strike using SPH modelling. Several assumptions have been made to model the bird as a gelatine structure and geometry and material model is utilised in this study. The bird model itself is modelled as a Smoothed Particle Hydrodynamics (SPH) to accurately represent a real bird impact especially during take-off and landing. As such, the engine blades impacted by the bird is modelled as a tetrahedron elements in commercial software of LS-DYNA. The engine is rotating in the z-axis at 200 rad/s counter-clockwise. The material of the blade is modelled with a Johnson-Cook failure constants. The numerical framework is validated with previous literature. The computational results are presented as effective stresses and shows that the structural damage due to impact is significant such that the bird strike causes deflection that will damage the engine blades