Investigation of stresses at the fixed end of deep cantilever beams

1998 ◽  
Vol 69 (3) ◽  
pp. 329-338 ◽  
Author(s):  
S.R. Ahmed ◽  
M.R. Khan ◽  
K.M.S. Islam ◽  
Md.W. Uddin
Keyword(s):  
Cantilever Beams ◽  
Fixed End

Estimation of the severity of damage produced by a transverse crack

2020 ◽  
Vol 65 (1) ◽  
pp. 137-144
Author(s):  
Marius-Vasile Pop
Keyword(s):  
Transverse Crack ◽  
Bending Moment ◽  
Cantilever Beams ◽  
Trend Line ◽  
The Real ◽  
Symmetrical Deformation ◽  
Frequency Drop ◽  
Equidistant Points ◽  
Fixed End ◽  
Crack Position

This paper presents a method to find the severity of a crack for cantilever beams that can be used to estimate the frequency drop due to the crack. The severity is found for the crack located at the location where the biggest curvature (or bending moment) is achieved. Because the fixing condition does not permit a symmetrical deformation around the crack, the apparent severity is smaller as the real one. The latter is found by the estimated value of the trend-line at the fixed end, it being constructed on points that consider the crack position (equidistant points in the proximity of the fixed end) and the resulted deflections.

scholarly journals Design and Non-Linear Analysis of a Parabolic Leaf Spring

1970 ◽  
Vol 37 ◽  
pp. 47-51 ◽  
Author(s):  
Muhammad Ashiqur Rahman ◽  
Muhammad Tareq Siddiqui ◽  
Muhammad Arefin Kowser
Keyword(s):  
Geometric Nonlinearity ◽  
Maximum Stress ◽  
Large Deflection ◽  
Linear Analysis ◽  
Leaf Spring ◽  
Cantilever Beams ◽  
Leaf Springs ◽  
Non Linear ◽  
Fixed End ◽  
Parabolic Leaf Spring

Tapered cantilever beams, traditionally termed as leaf springs, undergo much larger deflections in comparison to a beam of constant cross-section that takes their study in the domain of geometric nonlinearity. This paper studies response of a leaf spring of parabolic shape, assumed to be made of highly elastic steel. Numerical simulation was carried out using both the small and large deflection theories to calculate the stress and the deflection of the same beam. Non-linear analysis is found to have significant effect on the beam's response under a tip load. It is seen that the actual bending stress at the fixed end, calculated by nonlinear theory, is 2.30-3.39% less in comparison to a traditional leaf spring having the same volume of material. Interestingly, the maximum stress occurs at a region far away from the fixed end of the designed parabolic leaf spring. Keywords: Parabolic leaf spring, End-shortening, Geometric nonlinearity, Equilibrium Configuration Path, Varying Cross-section.doi:10.3329/jme.v37i0.819Journal of Mechanical Engineering Vol.37 June 2007, pp.47-51

scholarly journals Performance of Cantilever Beam in Fire

2017 ◽  
Vol 11 (1) ◽  
pp. 847-853
Author(s):  
Yuzhuo Wang ◽  
Xihu Gao ◽  
Debiao Zhu ◽  
Chuanguo Fu
Keyword(s):  
Cantilever Beam ◽  
Plastic Hinge ◽  
Cantilever Beams ◽  
Horizontal Section ◽  
Failure Data ◽  
Deformation Law ◽  
Bending Capacity ◽  
Fixed End ◽  
In Fire ◽  
Bending Failure

Introduction: This paper presents results from an experimental study on the temperature effect of reinforced concrete cantilever beam. Methods: Three cantilever beams with fixed end were tested in fire furnace, the distribution of temperature field, the deformation law and the fire resistance of the cantilever beam were obtained. Results: Results from these tests indicate that the horizontal section of the temperature curve is about 100 degrees centigrade. The bending capacity of the beam is weaken at high temperature and the failure mode of beam is bending failure. Data from tests also indicates that the plastic hinge of the end of beam moves outward about 240 mm.

Micro Cantilever Electrostatic Energy Harvester

2013 ◽  
Author(s):  
Bashar K. Hammad ◽  
Eihab M. Abdel-Rahman ◽  
Mohamed A. E. Mahmoud
Keyword(s):  
Energy Harvester ◽  
Nonlinear Effects ◽  
Electrostatic Energy ◽  
Design Parameters ◽  
Cantilever Beams ◽  
Response Curves ◽  
Electric Parameters ◽  
Micro Cantilever ◽  
Fixed End ◽  
Tip Mass

In this paper, we present a SDOF model of an energy harvester made up of microcantilever beams with tip mass. We investigate performance utilizing electrostatic actuation mechanism resulted from an electret layer patterned underneath the tip mass. The excitation force is transferred to cantilever beams through the vibration of the fixed end, i.e. the base of the beam. The model accounts for the mechanical and electric parameters as well as the coupling between them, and it includes design parameters by lumping them into nondimensional quantities, thereby allowing an easier understanding of their effects and the interaction between the mechanical and electric forces. We study the static behavior of deflection and electric charge as a function of the DC static voltage. In addition, we simulate the dynamic response, generate the frequency-response curves for a variety of conditions, and notice nonlinear effects.

Damage detection in cantilever beams using spatial Fourier coefficients of augmented modes

2016 ◽  
Vol 230 (20) ◽  
pp. 3677-3690 ◽  
Author(s):  
Ranjan Ganguli ◽  
Saipraneeth Gouravaraju
Keyword(s):  
Damage Detection ◽  
Cantilever Beam ◽  
Fourier Coefficients ◽  
Mirror Image ◽  
Fourier Series Expansion ◽  
Mode Shapes ◽  
Cantilever Beams ◽  
Periodic Mode ◽  
Considerable Impact ◽  
Fixed End

A mode shape based damage detection method for a cantilever beam is proposed in this paper. The idea involves use of spatial Fourier series expansion of mode shapes. Mode shapes of a cantilever beam are not periodic in nature. However, by taking their mirror image about the fixed end, an augmented periodic mode can be created which permits spatial Fourier analysis. It is observed using finite element simulations that damage has a considerable impact on the spatial Fourier coefficients of the mode shapes of a damaged beam. It is also found that the Fourier coefficients are sensitive to intensity of damage and its location on the beam. Sensitivity of the Fourier coefficients in presence of noise is also analyzed and they are found to be effective in indicating the damage.

Fixed-End Moment Equations for Continuous Prestressed Concrete Beams

PCI Journal ◽  
1966 ◽  
Vol 11 (1) ◽  
pp. 75-94
Author(s):  
Duryl M. Bailey ◽  
Phil M. Ferguson
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Moment Equations ◽  
Fixed End

Improved Autoadhesion Measurement Method for Micromachined Polysilicon Beams

1996 ◽  
Vol 444 ◽  
Author(s):  
Maarten P. de Boer ◽  
Terry A. Michalske
Keyword(s):  
Surface Chemistry ◽  
Optical Microscopy ◽  
Measurement Method ◽  
Current Practice ◽  
Cantilever Beams ◽  
Beam Length ◽  
Substrate Adhesion

AbstractWe have measured autoadhesion (e.g. stiction) of individual polysilicon beams by interferometric optical microscopy. Untreated cantilever beams were dried from water in air, while treated beams were coated with a hydrophobic molecular coating of octadecyltrichlorosilane (ODTS). Adhesion values obtained for beams adhered to the substrate over a long length (large d) are independent of beam length with values of 16.7 and 4.4 mJ/m2 for untreated and treated samples respectively. These values can be understood in terms of differences in surface chemistry and polysilicon roughness. Using the shortest length beam which remains attached to the substrate, adhesion values were 280 and 16 mJ/m2 respectively. These higher values may be a result of capillarity effects. We recommend that measurements be made on beams in which d is large, in contrast to the current practice of noting the shortest beam adhered.

Split beam method for determining mode shapes of cantilever beams under multiple loading conditions

2021 ◽  
pp. 107754632110276
Author(s):  
Jun-Jie Li ◽  
Shuo-Feng Chiu ◽  
Sheng D Chao
Keyword(s):  
Operation Mode ◽  
Point Contact ◽  
Mode Shapes ◽  
Cantilever Beams ◽  
Loading Conditions ◽  
Mechanical Responses ◽  
Relative Contribution ◽  
Resonance Frequencies ◽  
Beam Method ◽  
Multiple Loading

We have developed a general method, dubbed the split beam method, to solve Euler–Bernoulli equations for cantilever beams under multiple loading conditions. This kind of problem is, in general, a difficult inhomogeneous eigenvalue problem. The new idea is to split the original beam into two (or more) effective beams, each of which corresponds to one specific load and bears its own Young’s modulus. The mode shape of the original beam can be obtained by linearly superposing those of the effective beams. We apply the split beam method to simulating mechanical responses of an atomic force microscope probe in the “dynamical” operation mode, under which there are a stabilizing force at the positioner and a point-contact force at the tip. Compared with traditional analytical or numerical methods, the split beam method uses only a few number of basis functions from each effective beam, so a very fast convergence rate is observed in solving both the resonance frequencies and the mode shapes at the same time. Moreover, by examining the superposition coefficients, the split beam method provides a physical insight into the relative contribution of an individual load on the beam.

scholarly journals Magnetic Driven Two-Finger Micro-Hand with Soft Magnetic End-Effector for Force-Controlled Stable Manipulation in Microscale

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 410
Author(s):  
Dan Liu ◽  
Xiaoming Liu ◽  
Pengyun Li ◽  
Xiaoqing Tang ◽  
Masaru Kojima ◽  
...  
Keyword(s):  
Magnetic Force ◽  
Force Feedback ◽  
Soft Magnetic ◽  
End Effector ◽  
Force Microscopy ◽  
System A ◽  
Atomic Force ◽  
Afm Probe ◽  
End Effectors ◽  
Fixed End

In recent years, micromanipulators have provided the ability to interact with micro-objects in industrial and biomedical fields. However, traditional manipulators still encounter challenges in gaining the force feedback at the micro-scale. In this paper, we present a micronewton force-controlled two-finger microhand with a soft magnetic end-effector for stable grasping. In this system, a homemade electromagnet was used as the driving device to execute micro-objects manipulation. There were two soft end-effectors with diameters of 300 μm. One was a fixed end-effector that was only made of hydrogel, and the other one was a magnetic end-effector that contained a uniform mixture of polydimethylsiloxane (PDMS) and paramagnetic particles. The magnetic force on the soft magnetic end-effector was calibrated using an atomic force microscopy (AFM) probe. The performance tests demonstrated that the magnetically driven soft microhand had a grasping range of 0–260 μm, which allowed a clamping force with a resolution of 0.48 μN. The stable grasping capability of the magnetically driven soft microhand was validated by grasping different sized microbeads, transport under different velocities, and assembly of microbeads. The proposed system enables force-controlled manipulation, and we believe it has great potential in biological and industrial micromanipulation.

Sign in / Sign up

Export Citation Format

Share Document