The dynamic behavior of fractal-like tubes with Sierpinski hierarchy under axial loading

2021 ◽  
Author(s):  
Qiang He ◽  
Yonghui Wang ◽  
Hang Gu ◽  
Jun Feng ◽  
Honggen Zhou
Keyword(s):  
Dynamic Behavior ◽  
Axial Loading

Dynamic Behavior of Ice under Cyclic Axial Loading

1978 ◽  
Vol 104 (7) ◽  
pp. 801-814
Author(s):  
Ted S. Vinson ◽  
Thira Chaichanavong
Keyword(s):  
Dynamic Behavior ◽  
Axial Loading

scholarly journals Dynamic Analysis of Helical Planetary Gear Sets under Combined Force and Moment Loading

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Yanfang Liu ◽  
Junbin Lai ◽  
Peng Dong ◽  
Xiangyang Xu
Keyword(s):  
Dynamic Model ◽  
Dynamic Behavior ◽  
Three Dimensional ◽  
Axial Loading ◽  
Planetary Gear ◽  
Combined Loading ◽  
External Loading ◽  
Parameter Method ◽  
Vibration Responses ◽  
The Moment

The dynamic behavior of a single-stage planetary gear set with helical gears of multishaft automotive automatic transmissions has been studied, in which one component of the planetary gear set is imposed by additional external vertical and axial loading from countershaft gear pair in addition to the moment. Under these combined loading conditions, the contributions of the deflections of the ring gear and the carrier cannot be neglected. A three-dimensional nonlinear time-variant dynamic model considering not only the transverse, torsional, axial, and rotational motions of the gears but also the elasticity of the mounted shafts has been developed by combining the lumped parameter method with finite element method. The natural modes and the forced vibration responses due to static transmission errors have been obtained. The proposed dynamic model is employed to describe the effects of the combined external loading condition and positioning on the dynamic behavior of a four-planet system.

Mechanical Modeling and General Analytical Solution for the Dynamic Buckling of Plane Structures Using a Beam-Column Element with Varying End Restraints

2021 ◽  
Author(s):  
Aissam Beldjazia ◽  
Redouane Adman ◽  
Adel Slimani ◽  
Messaoud Saidani ◽  
Toufik Belaid ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Fundamental Frequency ◽  
Mechanical Model ◽  
Global Analysis ◽  
Axial Loading ◽  
Dynamic Buckling ◽  
Model Compression ◽  
The Stability ◽  
Stability Of Structures ◽  
Column Element

The stability of structures is an important aspect that the designer must pay particular attention to in order to ensure safety against collapse. This investigation is concerned with analytical and numerical analyses of the dynamic buckling of plane structures. A rigorous mechanical model is proposed, consisting of a beam-column element with nodal ends possessing two rotational springs of rigidities acting in parallel with the bending stiffness of the beam-column. The model is first analyzed with respect to the dynamic behavior by investigating the influence of the variation in the stiffness of the nodal springs on the fundamental frequency of the proposed mechanical model. Compression axial loading is applied to the beam-column in order to study the nonlinear dynamic behavior by introducing buckling. This novel approach is used to highlight the interaction between the fundamental frequency and the critical buckling load. Simple examples are treated using the approach and the results are compared with those obtained from a global analysis. The results revealed that it is possible to reproduce the stability analysis of a global structure by simply analyzing a target element, taking into account all elements adjacent to it with less than 1% error on the results.

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

Correlation of axial loaded magnetic resonance imaging with clinical symptoms in lumbar spinal canal stenosis patients

MedPharmRes ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 15-19
Author(s):  
Son Nguyen ◽  
Son Vi ◽  
Hoat Luu ◽  
Toan Do
Keyword(s):  
Spinal Canal ◽  
Clinical Symptoms ◽  
Axial Loading ◽  
Spinal Canal Stenosis ◽  
Leg Pain ◽  
Cross Sectional ◽  
Canal Stenosis ◽  
Conventional Mri ◽  
Frame System ◽  
Lumbar Spinal

There are cases when symptoms are available but no abnormal stenosis is found in MRI and vice versa. Axial-loaded MRI has been shown that it can demonstrate more accurately the real status of spinal canal stenosis than conventional MRI. This is the first time we applied a new system that we have recreated from the original loading frame system in order to fit with the demands of Vietnamese people. Sixty-two patients were selected from Phu Tho Hospital in Phu Tho Province, Vietnam, who fulfilled the inclusion criteria. The Anterior-posterior diameter (APD), Dura Cross-sectional Area (DSCA) in conventional MRI and axial loaded MRI, and changes in APD and DCSA were determined at the single most constricted intervertebral level. The APD and DCSA in axial loaded MRI had very good significant correlations with VAS for back pain (rs=0.83, 0.79), leg pain (rs=0.69, 0.57) and JOA score (rs=0.70, 0.65). APD and DCSA in axial loaded MRI significantly correlated with the severity of symptoms. Our axial loading MRI provides more valuable information than the conventional MRI for assessing patients with LSCS.

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