scholarly journals Analytical Model of Bolted Joint Structure and Its Nonlinear Dynamic Characteristics in Transient Excitation

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Xin Liao ◽  
Jianrun Zhang ◽  
Xiyan Xu
Keyword(s):  
Dynamic Response ◽  
Analytical Model ◽  
Nonlinear Behavior ◽  
Nonlinear Effects ◽  
Tangential Direction ◽  
Nonlinear Stiffness ◽  
Bolted Joint ◽  
Element Analysis ◽  
Simulation Results ◽  
Cubic Stiffness

The dynamic response of crucial components often depends upon the dynamic behavior of bolted connections. As is usually the case, the accurate modeling of structures with many mechanical joints remains a challenge work. The nonlinear behavior included in assembled structures strongly depends on the interface properties. In this paper, an analytical model of the simple bolted joint beam in tangential direction is first proposed for transient excitation, based on phenomenological model. The fourth-order Runge-Kutta method is employed to calculate the transient response, where the dynamic response of the nonlinear stiffness on system is also investigated. The simulation results show that natural frequency has a certain dependence on cubic stiffness term and cubic stiffness is more suitable for modeling of nonlinear system of a wider frequency range. Thereby, a series Iwan model containing cubic stiffness term is established to describe nonlinear behaviors of bolted joint beams in shear vibration. The amplitude-frequency curves show that the influence of interaction between nonlinear stiffness and damping mechanism on dynamic response characteristics is more obvious. Finally, a new type of nonlinear model is applied into finite element analysis. The results of proposed transient excitation experiment are discussed qualitatively, indicating that nonlinear effects observed agree with the numerical simulation results.

Multistable Cosine-Curved Dome System for Elastic Energy Dissipation

2019 ◽  
Vol 86 (9) ◽  
Author(s):  
Mansour Alturki ◽  
Rigoberto Burgueño
Keyword(s):  
Energy Dissipation ◽  
Analytical Model ◽  
Nonlinear Behavior ◽  
Experimental Tests ◽  
High Energy ◽  
Bistable System ◽  
Dissipated Energy ◽  
Element Analysis ◽  
The Individual ◽  
Hysteretic Response

This paper presents a new energy dissipation system composed of multistable cosine-curved domes (CCD) connected in series. The system exhibits multiple consecutive snap-through and snap-back buckling behavior with a hysteretic response. The response of the CCDs is within the elastic regime and hence the system's original configuration is fully recoverable. Numerical studies and experimental tests were conducted on the geometric properties of the individual CCD units and their number in the system to examine the force–displacement and energy dissipation characteristics. Finite element analysis (FEA) was performed to simulate the response of the system to develop a multilinear analytical model for the hysteretic response that considers the nonlinear behavior of the system. The model was used to study the energy dissipation characteristics of the system. Experimental tests on 3D printed specimens were conducted to analyze the system and validate numerical results. Results show that the energy dissipation mainly depends on the number and the apex height-to-thickness ratio of the CCD units. The developed multilinear analytical model yields conservative yet accurate values for the dissipated energy of the system. The proposed system offered reliable high energy dissipation with a maximum loss factor value of 0.14 for a monostable (self-recoverable) system and higher for a bistable system.

Nonlinear Behavior of Preloaded Bolted Joints Under a Cyclic Separating Load

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Xianjie Yang ◽  
Sayed A. Nassar ◽  
Zhijun Wu ◽  
Aidong Meng
Keyword(s):  
Finite Element ◽  
Deformation Behavior ◽  
Nonlinear Behavior ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Element Analysis ◽  
Linear Elastic ◽  
Plastic Deformation Behavior ◽  
Service Load ◽  
Joint Material

The nonlinear plastic deformation behavior of a clamped bolted joint model under a separating service load is investigated using analytical, finite element, and experimental techniques. An elastic-plastic model is used for the bolt material while the joint material remains in the linear elastic range. Both the analytical and finite element analysis (FEA) models investigate the variation in the tension of a preloaded bolt due to a separating service load that acts with an offset from the bolt center. Experimental verification is provided for both the analytical and finite element results on the bolt tension variation, clamp load variation and the clamp load loss caused by the incremental plastic bolt elongation under cyclic separating force.

Effects of Bearing Radial Internal Clearance on Dynamic Behavior and Bifurcations in Planetary Gears

2011 ◽  
Author(s):  
Yi Guo ◽  
Robert G. Parker
Keyword(s):  
Dynamic Response ◽  
Harmonic Balance Method ◽  
Nonlinear Behavior ◽  
Nonlinear Effects ◽  
Lumped Parameter Model ◽  
Solution Stability ◽  
Planetary Gears ◽  
Gear Mesh ◽  
Bearing Clearance ◽  
Lumped Parameter

This study investigates the dynamics of planetary gears where nonlinearity is induced by bearing clearance. Lumped-parameter and finite element models of planetary gears with bearing clearance, tooth separation, and gear mesh stiffness variation are developed. The harmonic balance method with arc-length continuation is used to obtain the dynamic response of the lumped-parameter model. Solution stability is analyzed using Floquet theory. Rich nonlinear behavior is exhibited in the dynamic response, consisting of nonlinear jumps and a hardening effect induced by the transition from no bearing contact to contact. The bearings of the central members (sun, ring, and carrier) impact against the bearing races near resonance, which leads to coexisting solutions in wide speed ranges, grazing bifurcation, and chaos. Secondary Hopf bifurcation is the route to chaos. Input torque can significantly suppress the nonlinear effects caused by bearing clearance.

Analytical, FEA and Experimental Methods for Computing the Resilience of Tapped Thread Joints

2011 ◽  
Author(s):  
Yosef Amir ◽  
John Reif ◽  
Nicholas Konkle
Keyword(s):  
Analytical Model ◽  
Analytical Methods ◽  
Dissimilar Materials ◽  
Experimental Methods ◽  
Bolted Joint ◽  
Element Analysis ◽  
Fea Modeling ◽  
Screw Joint ◽  
Basic Parameters ◽  
Analytical Approaches

Bolted joint behavior is based on many parameters, many of which are not well known or understood. The basic parameters describing the signature behavior of the bolted joint are the fastener and clamped joint flanges’ resilience. The level of confidence in the resilience parameter defines the confidence level of further analysis performed throughout the design phase. For general cases with simple configurations of the bolt and joint members, well-known analytical methods such as VDI 2230 satisfy the purpose of bolted joint analyses. However, in practice there are cases which deviate from the idealized joint, such as complex bolted joint geometry or dissimilar materials which cannot be simplified for an analytical model. The particular case studied here is that of a screw joint or tapped thread joint (TTJ) where the analytical model is ambiguous. In addition, for TTJs that are critical to safety a high confidence in the result is desired, so finite element analysis (FEA) or experimental methods are preferred to assess the resilience of the clamped and tapped flanges. This paper presents FEA modeling as well as analytical methods for complex joints, particularly for TTJ configurations. Resilience values for FEA and analytical approaches are presented, as well as experimental results for validation.

Predictive Modeling of the Dynamic Response of Electronic Systems to Shocks and Vibrations

2010 ◽  
Vol 63 (5) ◽  
Author(s):  
E. Suhir
Keyword(s):  
Dynamic Response ◽  
Predictive Modeling ◽  
Printed Circuit Boards ◽  
Nonlinear Behavior ◽  
Electronic Systems ◽  
Circuit Boards ◽  
Element Analysis ◽  
Portable Electronics ◽  
Flexible Printed Circuit ◽  
Board Level

The published work on analytical (“mathematical”) and computer-aided, primarily finite-element-analysis based, predictive modeling of the dynamic response of electronic systems to shocks and vibrations is reviewed. Understanding the physics and the ability to predict the response of an electronic structure to dynamic loading has been always of significant importance in military, avionic, aeronautic, automotive, and maritime electronics. For the past decade, this problem has become important also in commercial, and, particularly, in portable, electronics in connection with accelerated testing on the board level of various surface-mount technology systems. The emphasis of this review is on the nonlinear behavior of flexible printed circuit boards experiencing shock loading applied to their support contours.

A Reduced-Order Dynamic Model of Nonlinear Oscillating Devices

2007 ◽  
Vol 129 (4) ◽  
pp. 514-521
Author(s):  
R. Xu ◽  
K. Komvopoulos
Keyword(s):  
Dynamic Model ◽  
Driving Force ◽  
Nonlinear Response ◽  
Rotation Angle ◽  
Damping Ratio ◽  
Nonlinear Behavior ◽  
Nonlinear Stiffness ◽  
Reduced Order ◽  
Simulation Results ◽  
Nonlinear Devices

A reduced-order dynamic model is presented for nonlinear devices subjected to in-plane oscillatory motion. Comparisons between numerical and finite element results demonstrate that the nonlinear behavior of a planar resonator can be predicted accurately by the derived dynamic model with significantly less computation. Simulation results illustrate the effects of nonlinear stiffness, damping ratio, electrostatic driving force, and device dimensions on the nonlinear dynamic behavior. The analysis yields two possible stable responses, depending on the initial rotation angle and rotation rate. The present dynamic model can be easily modified to analyze the nonlinear response of various planar resonators.

Dynamic Response of the Surface Building under the Blasting Seismic Waves

2014 ◽  
Vol 602-605 ◽  
pp. 586-589
Author(s):  
Yu Shan Xu ◽  
Qiang Sun ◽  
Dong Xi Shi ◽  
Xue Jiao Zhang ◽  
Yi Feng Hu ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Seismic Waves ◽  
Structural Model ◽  
Residential Area ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Analysis Software ◽  
Element Analysis ◽  
Velocity Response ◽  
Simulation Results

This article selects relatively common residential area as the prototype and uses finite element analysis software ANSYS/LS-DYNA to establish a framework to simplify the model. Four scene measured vibration velocity are loaded on the structural model. The dynamic response under four different peaks blasting vibration velocity response is simulated, and the simulation results are summarized.

A Simplified Design Model for Modular Steel Buildings Subject to Vapor Cloud Explosions (VCEs)

2020 ◽  
Vol 14 ◽  
Author(s):  
Osama Bedair
Keyword(s):  
Dynamic Response ◽  
Minimum Cost ◽  
Design Parameters ◽  
Front Wall ◽  
Steel Buildings ◽  
Element Analysis ◽  
Analysis And Design ◽  
Vapor Cloud ◽  
Building Components ◽  
Analytical Expressions

Background: Modular steel buildings (MSB) are extensively used in petrochemical plants and refineries. Limited guidelines are available in the industry for analysis and design of (MSB) subject to accidental vapor cloud explosions (VCEs). Objectives: The paper presents simplified engineering model for modular steel buildings (MSB) subject to accidental vapor cloud explosions (VCEs) that are extensively used in petrochemical plants and refineries. Method: A Single degree of freedom (SDOF) dynamic model is utilized to simulate the dynamic response of primary building components. Analytical expressions are then provided to compute the dynamic load factors (DLF) for critical building elements. Recommended foundation systems are also proposed to install the modular building with minimum cost. Results: Numerical results are presented to illustrate the dynamic response of (MSB) subject to blast loading. It is shown that (DLF)=1.6 is attained at (td/t)=0.4 for front wall (W1) with (td/T)=1.25. For side walls (DLF)=1.41 and is attained at (td/t)=0.6. Conclusions: The paper presented simplified tools for analysis and design of (MSB) subject accidental vapor cloud blast explosions (VCEs). The analytical expressions can be utilized by practitioners to compute the (MSB) response and identify the design parameters. They are simple to use compared to Finite Element Analysis.

Evaluation of web reinforcements in prestressed concrete box girders through shear-transverse bending domains

2020 ◽  
pp. 136943322098170
Author(s):  
Michele Fabio Granata ◽  
Antonino Recupero
Keyword(s):  
Analytical Model ◽  
Prestressed Concrete ◽  
3D Analysis ◽  
Box Girders ◽  
Element Analysis ◽  
Cross Sectional ◽  
Interaction Domains ◽  
Global And Local ◽  
Resultant Forces

In concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical model allows an easy and reliable reinforcement evaluation, in agreement with a more refined 3D analysis but with a reduced computational burden.

scholarly journals Cheating at Craps

2021 ◽  
Vol 48 (4) ◽  
pp. 53-61
Author(s):  
Andrea Marin ◽  
Carey Williamson
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Modeling And Simulation ◽  
Analytical Model ◽  
Quantitative Evaluation ◽  
Mathematical Analysis ◽  
Simulation Modeling ◽  
Analytical Modeling ◽  
The World ◽  
Simulation Results

Craps is a simple dice game that is popular in casinos around the world. While the rules for Craps, and its mathematical analysis, are reasonably straightforward, this paper instead focuses on the best ways to cheat at Craps, by using loaded (biased) dice. We use both analytical modeling and simulation modeling to study this intriguing dice game. Our modeling results show that biasing a die away from the value 1 or towards the value 5 lead to the best (and least detectable) cheating strategies, and that modest bias on two loaded dice can increase the winning probability above 50%. Our Monte Carlo simulation results provide validation for our analytical model, and also facilitate the quantitative evaluation of other scenarios, such as heterogeneous or correlated dice.

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