Measurement of Pressure Distribution Between Contact Surfaces by Light Reflection

1996 ◽  
Vol 118 (1) ◽  
pp. 161-165
Author(s):  
K. Yamaguchi ◽  
M. Uchida ◽  
F. Mondori
Keyword(s):  
Pressure Distribution ◽  
Pressure Measurement ◽  
Three Dimensions ◽  
Light Reflection ◽  
Measuring Device ◽  
Pressure Distributions ◽  
Contact Surfaces ◽  
Reflection Of Light

In the present study, the authors propose a method to determine the pressure distribution acting on contact surfaces and detail the development of a measuring device. The principle of pressure measurement is based on the scattered reflection of light from the surface after contact. The device developed measures the pressure distribution and displays it in three dimensions. Pressure distributions measured on various contact surfaces are shown.

scholarly journals Effect of Pressure Distribution on the Energy Dissipation of Lap Joints under Equal Pre-tension Force

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 320-328
Author(s):  
Delin Sun ◽  
Minggao Zhu
Keyword(s):  
Energy Dissipation ◽  
Pressure Distribution ◽  
Theoretical Basis ◽  
Lap Joints ◽  
Power Exponent ◽  
Lap Joint ◽  
Stick Slip ◽  
Pressure Distributions ◽  
Hysteretic Characteristics ◽  
Effective Use

Abstract In this paper, the energy dissipation in a bolted lap joint is studied using a continuum microslip model. Five contact pressure distributions compliant with the power law are considered, and all of them have equal pretension forces. The effects of different pressure distributions on the interface stick-slip transitions and hysteretic characteristics are presented. The calculation formulation of the energy dissipation is introduced. The energy dissipation results are plotted on linear and log-log coordinates to investigate the effect of the pressure distribution on the energy distribution. It is shown that the energy dissipations of the lap joints are related to the minimum pressure in the overlapped area, the size of the contact area and the value of the power exponent. The work provides a theoretical basis for further effective use of the joint energy dissipation.

scholarly journals Dynamic flight load measurements with MEMS pressure sensors

2021 ◽  
Author(s):  
Christian Raab ◽  
Kai Rohde-Brandenburger
Keyword(s):  
Pressure Distribution ◽  
Pressure Sensors ◽  
Flow Characteristics ◽  
Flight Test ◽  
Measurement Technology ◽  
Test Program ◽  
Aerodynamic Pressure ◽  
Pressure Distributions ◽  
Time Histories ◽  
Mems Pressure Sensors

AbstractThe determination of structural loads plays an important role in the certification process of new aircraft. Strain gauges are usually used to measure and monitor the structural loads encountered during the flight test program. However, a time-consuming wiring and calibration process is required to determine the forces and moments from the measured strains. Sensors based on MEMS provide an alternative way to determine loads from the measured aerodynamic pressure distribution around the structural component. Flight tests were performed with a research glider aircraft to investigate the flight loads determined with the strain based and the pressure based measurement technology. A wing glove equipped with 64 MEMS pressure sensors was developed for measuring the pressure distribution around a selected wing section. The wing shear force determined with both load determination methods were compared to each other. Several flight maneuvers with varying loads were performed during the flight test program. This paper concentrates on the evaluation of dynamic flight maneuvers including Stalls and Pull-Up Push-Over maneuvers. The effects of changes in the aerodynamic flow characteristics during the maneuver could be detected directly with the pressure sensors based on MEMS. Time histories of the measured pressure distributions and the wing shear forces are presented and discussed.

scholarly journals Influence of the Spatial Pressure Distribution of Breaking Wave Loading on the Dynamic Response of Wolf Rock Lighthouse

2021 ◽  
Vol 9 (1) ◽  
pp. 55
Author(s):  
Darshana T. Dassanayake ◽  
Alessandro Antonini ◽  
Athanasios Pappas ◽  
Alison Raby ◽  
James Mark William Brownjohn ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Pressure Distribution ◽  
Distinct Element ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Wave Loading ◽  
Wave Impact ◽  
Pressure Distributions ◽  
Impact Area ◽  
The Impact

The survivability analysis of offshore rock lighthouses requires several assumptions of the pressure distribution due to the breaking wave loading (Raby et al. (2019), Antonini et al. (2019). Due to the peculiar bathymetries and topographies of rock pinnacles, there is no dedicated formula to properly quantify the loads induced by the breaking waves on offshore rock lighthouses. Wienke’s formula (Wienke and Oumeraci (2005) was used in this study to estimate the loads, even though it was not derived for breaking waves on offshore rock lighthouses, but rather for the breaking wave loading on offshore monopiles. However, a thorough sensitivity analysis of the effects of the assumed pressure distribution has never been performed. In this paper, by means of the Wolf Rock lighthouse distinct element model, we quantified the influence of the pressure distributions on the dynamic response of the lighthouse structure. Different pressure distributions were tested, while keeping the initial wave impact area and pressure integrated force unchanged, in order to quantify the effect of different pressure distribution patterns. The pressure distributions considered in this paper showed subtle differences in the overall dynamic structure responses; however, pressure distribution #3, based on published experimental data such as Tanimoto et al. (1986) and Zhou et al. (1991) gave the largest displacements. This scenario has a triangular pressure distribution with a peak at the centroid of the impact area, which then linearly decreases to zero at the top and bottom boundaries of the impact area. The azimuthal horizontal distribution was adopted from Wienke and Oumeraci’s work (2005). The main findings of this study will be of interest not only for the assessment of rock lighthouses but also for all the cylindrical structures built on rock pinnacles or rocky coastlines (with steep foreshore slopes) and exposed to harsh breaking wave loading.

Determination of Three-Dimensional Body Forms from Given Pressure Distribution Over Their Surfaces

1996 ◽  
Vol 40 (01) ◽  
pp. 22-27
Author(s):  
V. M. Pashin ◽  
V. A. Bushkovsky ◽  
E. L. Amromin
Keyword(s):  
Pressure Distribution ◽  
Three Dimensional ◽  
Bodies Of Revolution ◽  
Design Constraints ◽  
Pressure Distributions ◽  
Axisymmetric Bodies

A method for solving inverse three-dimensional problems in hydromechanics is proposed which makes it possible to fit desired pressure distributions within design constraints immediately in the course of calculations. Examples of the method of application are given for bodies of revolution in flows at nonzero drift angles. These flows are not axisymmetric. Bodies of revolution in them are very handy examples of demonstrations of the method, and these examples have many technical applications.

scholarly journals New didactic formulation of the laws of reflection of light

2017 ◽  
Vol 39 (2) ◽  
Author(s):  
Ángel Luis Pérez-Rodríguez ◽  
Guadalupe Martínez-Borreguero ◽  
María Isabel Suero-López
Keyword(s):  
Geometrical Optics ◽  
Light Reflection ◽  
Corner Reflector ◽  
Educational Value ◽  
Elastic Collisions ◽  
Reflection Of Light ◽  
The Law ◽  
New Formulation

This work presents a new formulation of the laws of reflection of light, and it is shown the equivalence between the new and the classic formulations. The proposed formulation has a significant educational value, as it allows drawing analogies between the phenomena of light reflection and elastic collisions, which are very well known by students. The new developed statement of the law of reflection allows the resolution of traditional problems of geometrical optics, and in some cases the solution is much simpler and more intuitive than that obtained using the traditional statement of the laws of reflection. As an example, this formulation is applied for the resolution of the classic reflection problem of the three plane mirrors forming a trirectangular trihedron, also known as corner reflector.

scholarly journals Contact Analysis of a Dry Friction Clutch System

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Oday I. Abdullah ◽  
Josef Schlattmann
Keyword(s):  
Pressure Distribution ◽  
Contact Stiffness ◽  
Load Condition ◽  
Accurate Estimation ◽  
Factors Affecting ◽  
Clutch System ◽  
System Pressure ◽  
Friction Clutch ◽  
Contact Surfaces ◽  
Dry Friction Clutch

The numerical simulation of the friction clutch system (pressure plate, clutch disc, and flywheel) during the full engagement period (assuming no slipping between contact surfaces) is carried out using finite element method. Two types of load condition considered affect on the clutch elements during the full engagement period are the contact pressure of diaphragm spring and the centrifugal force. The study of the pressure distribution between the contact surfaces and the factors affecting it is one of the fundamentals in the process of designing the friction clutch to obtain accurate estimation of the temperature distribution during the slipping period and the contact stresses during the full engagement period. The investigation covers the effect of the contact stiffness factor FKN on the pressure distribution between contact surfaces, stresses, and penetration. The penalty and augmented Lagrange algorithms have been used to obtain the pressure distribution between contact surfaces. ANSYS13 software has been used to perform the numerical calculation in this paper.

Measurement of Seat Pressure Distributions

1987 ◽  
Vol 29 (5) ◽  
pp. 563-575 ◽  
Author(s):  
Delia Treaster ◽  
W. S. Marras
Keyword(s):  
Pressure Distribution ◽  
Video Signals ◽  
Optical Reflection ◽  
Pressure Distributions ◽  
Experimental Apparatus ◽  
Image Digitization ◽  
Novel Method ◽  
Measurement And Evaluation ◽  
Peak Pressures ◽  
Chair Design

Knowledge of seating pressures is important for proper chair design. This study demonstrates the usefulness of a new methodology for measuring pressure distributions. It refines and advances an optical-reflection technique introduced several years ago. In this way precise quantitative measures of the pressure distribution can be obtained. Video image digitization, which converts analog video signals to digital ones, provided data in a form that could be easily submitted for computer analysis. Additionally, a novel method of analysis is presented that allows for the measurement and evaluation of the distribution of seated pressures, rather than peak pressures alone. A preliminary experiment with eight subjects was conducted to demonstrate the validity of the experimental apparatus and the data treatment.

Feet Plantar Pressure Distribution Among Female School Teachers

2020 ◽  
Author(s):  
Ayuni Nabilah Alias ◽  
Karmegam Karuppiah ◽  
Vivien How ◽  
Velu Perumal
Keyword(s):  
Pressure Distribution ◽  
Pressure Measurement ◽  
Plantar Pressure ◽  
Significant Finding ◽  
School Teachers ◽  
Plantar Pressure Distribution ◽  
Starting Point ◽  
The Right

Abstract Background: Plantar pressure distribution has been recognized as a significant finding to associate with various feet conditions. Objectives: To determine the feet plantar pressure distribution among female school teachers; Methods: This research consisted of 124 female school teachers. Respondents was asked to walk at a regular pace for 10 seconds from a fixed starting point while using footwear pressure insole device and pressure measurement was recorded.; Results: The findings show that lateral heel exerted the most pressure in the right and left foot (94 kPa vs 85 kPa). The second highest average of plantar pressure distribution for right foot among female school teachers was medial forefoot (67 kPa), followed by central forefoot (55 kPa), lateral forefoot (52 kPa) and lateral midfoot with 49 kPa. For the left foot, the second highest for average of plantar pressure distribution was medial forefoot (58 kPa), followed by lateral forefoot (48 kPa), and central forefoot (47 kPa) and lateral midfoot (33 kPa). The result was significant differences as the right foot often exerted greater pressure on any part of the foot than the left foot; Conclusions: The pressure plantar distribution of foot reflects the conditions of school teachers with various posture and movement.

scholarly journals Plantar pressure distribution evaluation in children with down syndrome from 2 to 5 years old

2019 ◽  
Vol 32 ◽  
Author(s):  
Paula Silva de Carvalho Chagas ◽  
Riuraly Caroline Barreiros Fortunato Rangel ◽  
Sulamita Saile de Jesus Oliveira Dornelas ◽  
Anderson Daibert Amaral ◽  
Flávio Augusto Teixeira Ronzani ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Pressure Distribution ◽  
Plantar Pressure ◽  
Cross Sectional Study ◽  
Measurement Instruments ◽  
Standing Posture ◽  
Cross Sectional ◽  
Plantar Pressures ◽  
Pressure Distributions ◽  
Plantar Pressure Distribution

Abstract Introduction: Some peculiar features of Down Syndrome (DS), such as ligament laxity, hypotonia, delay in gait acquisition, among others, may generate alterations in the distribution of plantar pressures, modifying the plantar support. Objective: To verify whether there are differences in the evaluation of plantar pressure distributions in standing posture between the measurement instruments (Baropodometer, SAPO, and Radiography). Method: This was a cross-sectional study, evaluating ten children with SD and ten children with normal development (ND), aged from two to five years old. Bio-photogrammetry, baropodometry, and foot radiography were used to assess the plantar pressure distribution. Kappa analysis was used to evaluate the agreement index between the different instruments. Results: Children with DS and ND had a higher prevalence of pronated feet in all three instruments, with poor to substantial agreement among the instruments. Conclusion: According to this study instruments, there was a greater prevalence of pronated feet in the two groups . Differences in the evaluation of the distribution of plantar pressures in the standing posture between the Baropodometer, SAPO, and radiography were observed. These instruments should be used in a complementary manner, as they propose to evaluate different aspects of the feet alignment.

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