Impact Response Measurement of Contact Lenses

2015 ◽  
Vol 643 ◽  
pp. 173-177
Author(s):  
Kazuhide Watanabe ◽  
Naoki Miyashita ◽  
Du Hong Bin ◽  
Kyohei Irisa ◽  
Akihiro Takita ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Contact Lenses ◽  
Impact Force ◽  
Inertial Force ◽  
Small Mass ◽  
High Accuracy ◽  
Impact Response ◽  
Linear Motion ◽  
Response Measurement ◽  
The Impact

Impact response of contact lenses is measured using the Levitation Mass Method (LMM). In the LMM, a small mass collides with contact lenses and the impact force is measured with high accuracy as the inertial force of the moving part. A pneumatic linear bearing is used to achieve linear motion with sufficiently small friction acting on the moving part. Hysteresis loop and consumed energy as mechanical characteristics of contact lenses are also calculated.

Measurement of Dynamic Responses of a Force Sensor against Small Impact Forces with Various Durations

2016 ◽  
Vol 698 ◽  
pp. 73-79
Author(s):  
Naoki Miyashita ◽  
Kazuhide Watanabe ◽  
Akihiro Takita ◽  
Mitra Djamal ◽  
Takao Yamaguchi ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Impact Force ◽  
Inertial Force ◽  
Force Sensor ◽  
Small Mass ◽  
High Accuracy ◽  
Dynamic Responses ◽  
Linear Motion ◽  
Impact Forces ◽  
The Impact

At present, a method for evaluating dynamic characteristics of force sensors against small and short-duration impact forces has been developed. In this method, a small mass collides with a force sensor and the impact force is measured with high accuracy as the inertial force of the mass. A pneumatic linear bearing is used in order to realize linear motion with sufficiently small friction acting on the mass, i.e., the moving part of the bearing. Using this method, the dynamic characteristics of the force sensor are evaluated in detail: small and various-duration impact forces with maximum values of approximately 0.4-6.0 N and full width at half maximum (FWHM) of approximately 0.6-2.8 ms are applied to the force sensor and the impact responses of the force sensor are evaluated.

DYNAMIC CHARACTERISTICS MEASUREMENTS OF A FORCE TRANSDUCER AGAINST SMALL AND SHORT-DURATION IMPACT FORCES

2014 ◽  
Vol 21 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Mitra Djamal ◽  
Kazuhide Watanabe ◽  
Kyohei Irisa ◽  
Irfa Aji Prayogi ◽  
Akihiro Takita ◽  
...  
Keyword(s):  
Short Duration ◽  
Dynamic Characteristics ◽  
Impact Force ◽  
Inertial Force ◽  
Small Mass ◽  
Force Transducer ◽  
Force Transducers ◽  
Impact Forces ◽  
Maximum Impact Force ◽  
The Impact

Abstract A method for evaluating the dynamic characteristics of force transducers against small and short-duration impact forces is developed. In this method, a small mass collides with a force transducer and the impact force is measured with high accuracy as the inertial force of the mass. A pneumatic linear bearing is used to achieve linear motion with sufficiently small friction acting on the mass, which is the moving part of the bearing. Small and short-duration impact forces with a maximum impact force of approximately 5 N and minimum half-value width of approximately 1 ms are applied to a force transducer and the impulse responses are evaluated.

Impact Response Measurement of Poly-Urethane Sheet Using an Optical Interferometer

2017 ◽  
Vol 29 (3) ◽  
pp. 613-618
Author(s):  
Sa-nga Songmuang ◽  
◽  
Akihiro Takita ◽  
Suphanchai Punthawanunt ◽  
Keyword(s):  
High Speed ◽  
Impact Force ◽  
Inertial Force ◽  
Spherical Body ◽  
The Body ◽  
Impact Response ◽  
Optical Center ◽  
Optical Interferometer ◽  
Cube Corner ◽  
The Impact

[abstFig src='/00290003/16.jpg' width='300' text='The changes impact force to the sheet' ] A method for measuring the impact response of a polyurethane sheet is proposed. In the method, the velocity, acceleration, force, and displacement of a spherical body dropping onto the polyurethane sheet is measured using an optical interferometer. Only the velocity is measured from the Doppler shift of the laser light reflected on the cube corner prism embedded inside the spherical body. The optical center of the cube corner prism is made to coincide with the center of gravity of the whole spherical body to minimize the effect of the attitude change of the body. The acceleration, displacement, and inertial force of the body are calculated from the velocity. The dropping body is also observed using a high-speed camera. The uncertainty in measuring the instantaneous value of the impact force with a sampling interval of approximately 0.1 ms is estimated to be 0.23 N, which corresponds to 0.14% of the maximum force of approximately 1.60×102N. In the experiment, 10 drop measurements are conducted and show good reproducibility of this method.

Vibration Analysis of Different Micro-Beams with Laser Ablation

2013 ◽  
Vol 462-463 ◽  
pp. 428-431
Author(s):  
Liang Cai Xiong ◽  
Quan Sheng Zhou ◽  
Peng Chen
Keyword(s):  
Laser Ablation ◽  
Dynamic Response ◽  
Vibration Analysis ◽  
Laser Excitation ◽  
Impact Force ◽  
Laser Doppler Vibrometer ◽  
Impact Response ◽  
Vibration Velocity ◽  
Laser Shock ◽  
The Impact

The dynamic response of different micro-beams after laser excitation experiments have been investigated in this paper. The impact force that induces the vibration of micro-beams is the interaction of focused pulse laser and tested beams. The impact response of micro-beams after being excited is measured by Laser Doppler Vibrometer. Different beams such as cantilever beam, L-shaped beam are employed in our experiments. Comparisons of the vibration velocity and its frequencies of different beams have also been performed. Experimental results show that the mechanical effects of laser shock do really exist and can be utilized.

scholarly journals Experimental study of the impact response of geocells as components of rockfall protection embankments

2009 ◽  
Vol 9 (2) ◽  
pp. 459-467 ◽  
Author(s):  
S. Lambert ◽  
P. Gotteland ◽  
F. Nicot
Keyword(s):  
Experimental Study ◽  
Numerical Model ◽  
Boundary Conditions ◽  
Composite Structures ◽  
Impact Force ◽  
Impact Response ◽  
Rigid Base ◽  
Transmitted Force ◽  
The Impact ◽  
Rockfall Protection

Abstract. Rockfall protection embankments are ground levees designed to stop falling boulders. This paper investigates the behaviour of geocells to be used as components of these structures. Geocells, or cellular confinement systems, are composite structures associating a manufactured envelope with a granular geomaterial. Single cubic geocells were subjected to the impact resulting from dropping a spherical boulder. The geocells were filled with fine or coarse materials and different boundary conditions were applied on the lateral faces. The response is analysed in terms of the impact force and the force transmitted by the geocell to its rigid base. The influence on the geocell response of both the fill material and the cell boundary conditions is analysed. The aim was to identify the conditions resulting in greatest reduction of the transmitted force and also to provide data for the validation of a specific numerical model.

scholarly journals Experimental Investigation of Impact Response of RC Slabs with a Sandy Soil Cushion Layer

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Jianli Wu ◽  
Guotao Ma ◽  
Zhenhua Zhou ◽  
Xuefeng Mei ◽  
Xiewen Hu
Keyword(s):  
Layer Thickness ◽  
Sandy Soil ◽  
Failure Modes ◽  
Impact Force ◽  
Concrete Slab ◽  
Failure Process ◽  
Impact Response ◽  
Rc Slabs ◽  
Cushion Layer ◽  
The Impact

The impact response of reinforced-concrete (RC) slabs covered with a sandy soil cushion layer was investigated using an outdoor rockfall impact test platform. Impact tests were carried out by releasing rockfalls with different weights from different heights to impact a combined structure. Test data included the acceleration duration curve of the rockfall, strain of the concrete slab at multiple measuring points, and midpoint displacement duration curve of the slab. The test results showed an exponential relationship between the impact force acting on the cushion layer surface and cushion layer thickness. An empirical formula was used to calculate the maximum penetration, and the result was in good agreement with the test value. In addition, the attenuation rate of the impact force acting on the cushion layer increased exponentially with the increase in the cushion layer thickness, and the peak impact force could be attenuated by approximately 70% at a thickness of 0.6 m. Finally, the failure process and failure modes of the RC slabs were investigated.

Impact Response Spectrum for Design of Ship-Bridge Collisions

2014 ◽  
Vol 587-589 ◽  
pp. 1547-1553 ◽  
Author(s):  
Jun Jie Wang ◽  
Zhi Ran Yu
Keyword(s):  
Impact Force ◽  
Response Spectrum ◽  
Degree Of Freedom ◽  
Impact Response ◽  
Amplification Effect ◽  
Spectrum Method ◽  
Time Histories ◽  
Dynamic Amplification ◽  
Force Time ◽  
The Impact

Due to the complexity involved and limited study on the topic, the equivalent static method, adopted in the current codes for structural design of bridges under ship collisions, does not take into account the dynamic amplification effect correctly. An accurate assessment of impact force based on refined numerical simulation is time consuming and is normally too complex for ordinary design procedure. Herein, with reference to the earthquake response spectrum method, an impact response spectrum method, which considers the dynamic amplification effect and is efficient for design, is proposed. Through refined numerical simulations of ship-rigid wall collisions, 81 impact force time histories associated with 9 typical ships under 9 velocities are obtained. The dynamic magnification factor (DMF) of single-degree-of-freedom (SDOF) systems with different periods and damping ratios experiencing the 81 impact force time histories are then studied. The relationship of DMF and period under different damping ratios, i.e. the DMF spectrum, is yielded by statistical analysis, based on which the impact response spectrum is obtained. Finally, the design combination method for multi-degree-of-freedom based on the impact response spectrum of SDOF is discussed for a continuous beam bridge.

Linking the Impact Force History with Residual Mechanical Characteristics and NDI - A Smart Way to Perform SHM in Composites

2008 ◽  
Vol 56 ◽  
pp. 524-529 ◽  
Author(s):  
Nicolae Constantin ◽  
Viorel Anghel ◽  
Mircea Găvan ◽  
Ştefan Sorohan
Keyword(s):  
Composite Materials ◽  
Mechanical Characteristics ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Impact Force ◽  
Layered Composite ◽  
Damage Level ◽  
Clear Link ◽  
Post Impact ◽  
The Impact

Structural integrity monitoring (SHM) and evaluation of residual mechanical performance are highly needed in assessing the post-impact behaviour of composite materials and structures. The link between impact force history and the damage level was not followed enough in research studies upon the SHM of composites. The authors put in evidence a clear link in this matter in a variety of layered composite materials. The link was assessed by evaluating the residual mechanical performance and by nondestructive inspection (NDI) – ultrasonics and infrared thermography (IRT) - on the impacted samples. Such a link may prove a very useful and reliable shortcut for backing the online SHM and condition based maintenance.

Effect of Flexibility in Transverse Impact Problems

1997 ◽  
Author(s):  
Ahmet S. Yigit ◽  
Andreas P. Christoforou
Keyword(s):  
Multibody Systems ◽  
Computational Models ◽  
Functional Relationship ◽  
Impact Force ◽  
Impact Response ◽  
Flexible Body ◽  
Transverse Impact ◽  
Impact Problems ◽  
Maximum Impact Force ◽  
The Impact

Abstract The nature of impact response of a flexible body is studied. The key parameters which govern the nature of impact response are identified. The effects of these parameters on the impact response are examined through numerical simulations. It is shown that the normalized impact force and the type of impact response can be predicted through the functional relationship between the normalized maximum impact force and two nondimensional parameters termed as “loss factor” and “relative stiffness”. It is expected that the results of this study will be of great value in choosing adequate impact and computational models for the dynamic analysis of multibody systems subject to transverse impacts.

The Low-Velocity Impact Response of Sandwich Panels

2010 ◽  
Vol 168-170 ◽  
pp. 1149-1152
Author(s):  
Xiao Xiong Zha ◽  
Hong Xin Wang
Keyword(s):  
Impact Force ◽  
Energy Levels ◽  
Impact Resistance ◽  
Sandwich Panels ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Weight Impact ◽  
The Impact

The low velocity impact response of sandwich panels at different energy levels has been investigated by conducting drop-weight impact tests using an instrumented falling-weight impact tower. Impact parameters like maximum impact force and the extent of the damage were evaluated and compared for different types of sandwich panels. Finite elements simulations have been undertaken using the LS-DYNA software; the results of FE simulations have a good agreement with the experiments. It shows that, the impact force increased with thickness of face-sheets and foam core, the extent of the damage increased with the impact energy, sandwich panels with steel face sheet has a good impact resistance in comparison with sandwich panel with aluminum face sheets.

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