Identification of Weakly Nonlinear Systems Using Describing Function Inversion

Jalali, Hassan; Bonab, Behzad T; Ahmadian, Hamid

doi:10.1007/s11340-010-9375-x

Cited by 8 publications

(3 citation statements)

References 16 publications

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“…An innovative analytical model was created in order to determine the real correlation among load and deformation of a single bolted lap joint. Also natural frequencies and mode shapes were additionally identified [19], achieved modelling of aluminium honeycomb panel for identification of the parameters using several bolts [6,20] nonlinear dynamic characteristics under transient excitation [21] and using describing function inversion for determining weak non-linear system [22,23]. An identification method for analytical and numerical issues using the dynamic characteristic equation for linear interface parameters is presented by Jalali [24].…”

Section: Introductionmentioning

confidence: 99%

Non-linear modeling and parameter identification of a bolted joint using substructure synthesis theory

Hussain,

Ingole

2024

Eng. Res. Express

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Engineering applications require accurate modeling and parameter identification to anticipate bolted joint behavior under different loading circumstances. Bolted joints are extensively used in civil and mechanical structures. In this research study, cubic stiffness non-linearity is examined and a comprehensive model, which can exhibit the non-linearity of joint behavior, is developed. This is achieved by modeling the bolted joint which is connected at one end of a cantilever beam. Mathematical model is established using concept of sub structure synthesis theory by considering non-linear translational stiffness and non-linear rotational stiffness as a boundary condition. Non-dimensional natural frequencies are estimated by assuming stiffness parameters and joint parameter estimation for translational spring having nonlinear stiffness is calculated using second order curve fitting technique. Furthermore, estimated and exact value of cubic stiffness coefficient are compared. The experimental results shows that the percentage error of estimation for all the modes are less than 8 %. The experimentally determined natural frequencies are further contrasted with an analytical results to validate a precision of generated model. Present work contributes in improving the bolted joint analysis by providing a solid non-linear modeling and parameter identification methodology. This methodology enhances design practices and ensures the durability of engineering structures and mechanical systems by improving bolted joint comprehension.

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Section: Introductionmentioning

confidence: 99%

Non-linear modeling and parameter identification of a bolted joint using substructure synthesis theory

Hussain,

Ingole

2024

Eng. Res. Express

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“…Finding the nonlinear forces corresponding to the measured describing functions is called describing function inversion [6]. In this paper, nonlinear system identification using describing function is introduced briefly.…”

Section: Introductionmentioning

confidence: 99%

On the inversion of describing functions in nonlinear system analysis

Du¹,

Li²,

Ahlin³

2017

Vib. proced.

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Abstract. Nonlinear mechanical vibrations are widely found in engineering structures. Traditional linear analysis methods are failing to meet the growing requirements of analysis accuracy. Because of the complexity of nonlinear system, there is no general method for nonlinear system analysis. Based on the describing function method, a polynomial inversion method may be used in nonlinear system identification. Using this method, the measured DF can be inverted into the form of force which has a clearer physical meaning and is easier to use for parameter fit. A MDOF system with two types of nonlinearities at the same location is studied to demonstrate this method.

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“…Bograd et al [14] gave an overview of various joint types, their characteristics, and the models used for their simulation as well as an extensive information of up-to-date literature associated with this topic. Jalali et al [15] studied the weakly nonlinear systems of multiple degrees of freedom by describing functions inversion. Morelli [16] developed a new method for the structures to identify transfer function models from the noisy data.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Modeling and Identification of an Aluminum Honeycomb Panel with Multiple Bolts

Wen¹,

Chen²

2016

Shock and Vibration

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This paper focuses on the nonlinear dynamics modeling and parameter identification of an Aluminum Honeycomb Panel (AHP) with multiple bolted joints. Finite element method using eight-node solid elements is exploited to model the panel and the bolted connection interface as a homogeneous, isotropic plate and as a thin layer of nonlinear elastic-plastic material, respectively. The material properties of a thin layer are defined by a bilinear elastic plastic model, which can describe the energy dissipation and softening phenomena in the bolted joints under nonlinear states. Experimental tests at low and high excitation levels are performed to reveal the dynamic characteristics of the bolted structure. In particular, the linear material parameters of the panel are identified via experimental tests at low excitation levels, whereas the nonlinear material parameters of the thin layer are updated by using the genetic algorithm to minimize the residual error between the measured and the simulation data at a high excitation level. It is demonstrated by comparing the frequency responses of the updated FEM and the experimental system that the thin layer of bilinear elastic-plastic material is very effective for modeling the nonlinear joint interface of the assembled structure with multiple bolts.

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Identification of Weakly Nonlinear Systems Using Describing Function Inversion

Cited by 8 publications

References 16 publications

Non-linear modeling and parameter identification of a bolted joint using substructure synthesis theory

Non-linear modeling and parameter identification of a bolted joint using substructure synthesis theory

On the inversion of describing functions in nonlinear system analysis

Nonlinear Modeling and Identification of an Aluminum Honeycomb Panel with Multiple Bolts

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