Influence Coefficients of Tapered Cantilever Beams Computed on SEAC

1953 ◽  
Vol 20 (1) ◽  
pp. 131-133
Author(s):  
Samuel Levy
Keyword(s):  
Cantilever Beam ◽  
Computing Time ◽  
National Bureau ◽  
Cantilever Beams ◽  
Automatic Computer ◽  
Influence Coefficients ◽  
Basic Code ◽  
The Given

Abstract A description is given of a method for computing the influence coefficients in bending of a nonuniform cantilever beam using a basic code devised for the National Bureau of Standards electronic automatic computer SEAC. The given data for a particular problem are n, the number of stations at which influence coefficients are desired; EI0, EI1, … EIn, the bending stiffnesses at the root and at successive stations; and l1, l2, … ln, the distances between these stations. The basic code can be used in any case where the number of stations n is fewer than 23. In an example for a beam having 9 stations, the computing time was 3 min.

A Ritz Model of Unsteady Oil-Film Forces for Nonlinear Dynamic Rotor-Bearing System

2004 ◽  
Vol 71 (2) ◽  
pp. 219-224 ◽  
Author(s):  
Tiesheng Zheng ◽  
Shuhua Yang ◽  
Zhonghui Xiao ◽  
Wen Zhang
Keyword(s):  
Free Boundary ◽  
Ritz Method ◽  
Computing Time ◽  
Force Model ◽  
The Finite Element Method ◽  
Oil Film ◽  
Great Saving ◽  
Cavitation Region ◽  
The Given ◽  
Oil Film Pressure

Based on the free boundary theory and variational method, this paper presents a Ritz method to compute the instantaneous hydrodynamic forces of a real bearing subject to any perturbed motions of the rotor. The given method manipulates the cavitation region by simply introducing a parameter to match the free boundary condition and, as a result, a very simple approximate formula of oil-film pressure were obtained leading to great saving of computing time. The numerical examples show the high accuracy of the proposed formulas. This oil-film force model is also used to analyze the nonlinear dynamics of a rigid unbalanced rotor with elliptical bearing support. The results well agree with those of the oil-film force model computed by the finite element method and the computing time is saved greatly.

scholarly journals Calibration of Design Buckling Curves for Lateral-Torsional Buckling of Cantilever Beams Made of Glass—Experimental and Numerical Investigations

2019 ◽  
Vol 9 (16) ◽  
pp. 3432
Author(s):  
Ralph Timmers ◽  
Tobias Neulichedl
Keyword(s):  
Cantilever Beam ◽  
Cantilever Beams ◽  
Testing Device ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Numerical Investigations ◽  
Buckling Behavior ◽  
Load Carrying ◽  
Special Case ◽  
Important System

Using glass as a primary load-carrying element is becoming more and more popular in architecture. Probably the most used application is the single-span girder, but another important system is the cantilever beam, which is widely used, e.g., as a canopy in front of an entrance. Research on the lateral-torsional buckling behavior of glass beams has been typically performed on single-span girders. As a consequence, the design buckling curves provided in literature are usually too conservative for the widely used case of a cantilever beam, which is also related to the loading situation. Therefore, experimental and numerical investigations have been performed for this special case. Based on the obtained results, design buckling curves have been developed and resulted in being more economical than the curves already given in the literature. Among others, information on the shape and size of the real imperfections, a testing device for cantilever beams, and experimentally and numerically obtained load-deflection curves are additional outcomes of the investigations presented here.

Structural Design and Testing of a Butterfly Piezoelectric Generator with Multilayer Cantilever Beams

2013 ◽  
Vol 655-657 ◽  
pp. 823-829 ◽  
Author(s):  
Zhi Lin Ruan ◽  
Jun Jie Gong ◽  
Meng Chang Cai ◽  
Bing Huang
Keyword(s):  
Resonant Frequency ◽  
Cantilever Beam ◽  
Structural Design ◽  
Output Voltage ◽  
Experimental Setup ◽  
Cantilever Beams ◽  
Material Parameters ◽  
Piezoelectric Cantilever ◽  
Piezoelectric Generator ◽  
Design And Testing

In order to solve the inconsistent problem of multi-layer connection and vibration in each layer, a butterfly piezoelectric generator with multilayer cantilever beams is designed. The generator is mainly constituted by butterfly multilayer cantilever beams and mass subassembly two parts. Physical devices of butterfly generator and typical piezoelectric cantilever are fabricated respectively. The experimental setup is also put up for the testing of resonant frequency and output voltage. It can be found that each layer of multilayer generator has a similar output voltage and resonant frequency to the typical one with same geometric and material parameters. So each layer in butterfly piezoelectric generator can be simplified as a typical cantilever beam for researching and analyzing.

Modal and Aeroelastic Analysis of a Compressor Blisk Considering Mistuning

2011 ◽  
Author(s):  
Jens Nipkau ◽  
Arnold Ku¨hhorn ◽  
Bernd Beirow
Keyword(s):  
Equations Of Motion ◽  
Computing Time ◽  
Element Model ◽  
Forced Response ◽  
Lumped Mass ◽  
Aerodynamic Forces ◽  
Mass Model ◽  
Influence Coefficients ◽  
Aeroelastic Analysis ◽  
Lumped Mass Model

Focussing on three basic blade modes the effect of the flow’s influence on the forced response of a mistuned HPC-blisk is studied using a surrogate lumped mass model called equivalent blisk model (EBM). Both measured and intentionally allowed mistuning is considered to find out in principle if the flow contributes to a slowdown of blade displacements with increasing mistuning. In a first step the mechanical properties of the EBM are adjusted to a finite element model and known mistuning distributions given in terms of blade frequencies and damping. Taking into account the flow structure interaction CFD-computations are carried out in order to derive aerodynamic influence coefficients (AIC) which are used to describe the aerodynamic forces coming along with the motion of each blade in the flow. These aerodynamic forces can be included directly in the EBM equations of motion or alternatively be used to calculate aeroelastic eigenvalues from which additional equivalent aerodynamic elements representing the co-vibrating air mass as well as aerodynamic stiffening and damping effects are derived. Both kinds of EBM are applied to study the forced response at least in a qualitative manner aiming to demonstrate some basic effects at low computing time.

Design of a Non-Powered MEMS High G Shock Sensor

2008 ◽  
Author(s):  
Y. P. Wang ◽  
R. Q. Hsu ◽  
C. W. Wu
Keyword(s):  
Reaction Time ◽  
Cantilever Beam ◽  
Measurement Range ◽  
Cantilever Beams ◽  
Test Results ◽  
Triggering Mechanism ◽  
Spring Mechanism ◽  
The Impact

Conventional shock sensors typically use mechanisms such as cantilever beams or axial springs as triggering devices. Reaction time for these conventional shock sensors are either far too slow or, in many cases, fail to function completely for high G (>300G) applications. In this study, a non-powered MEMS high G shock sensor with a measurement range of 3,000–21,000 G is presented. The triggering mechanism is a combination of cantilever and spring structure. The design of the mechanism underwent a series of analyses. Simulation and test results indicated that a MEMS high G shock sensor has a faster reaction time than conventional G shock sensors that use a cantilever beam or spring mechanism. Furthermore, the MEMS high G shock sensor is sufficiently robust to survive the impact encountered in high G application where most conventional G shock sensors fail.

scholarly journals Solving the Large-Scale TSP Problem in 1 h: Santa Claus Challenge 2020

2021 ◽  
Vol 8 ◽  
Author(s):  
Radu Mariescu-Istodor ◽  
Pasi Fränti
Keyword(s):  
Large Scale ◽  
Computing Time ◽  
Real Life ◽  
Problem Instance ◽  
Santa Claus ◽  
Design Choice ◽  
Long Time ◽  
Problem Instances ◽  
The Given ◽  
Important Design

The scalability of traveling salesperson problem (TSP) algorithms for handling large-scale problem instances has been an open problem for a long time. We arranged a so-called Santa Claus challenge and invited people to submit their algorithms to solve a TSP problem instance that is larger than 1 M nodes given only 1 h of computing time. In this article, we analyze the results and show which design choices are decisive in providing the best solution to the problem with the given constraints. There were three valid submissions, all based on local search, including k-opt up to k = 5. The most important design choice turned out to be the localization of the operator using a neighborhood graph. The divide-and-merge strategy suffers a 2% loss of quality. However, via parallelization, the result can be obtained within less than 2 min, which can make a key difference in real-life applications.

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