Pressure distribution in the radiocarpal joint measured with a densitometer designed for pressure-sensitive film

1991 ◽  
Vol 16 (3) ◽  
pp. 401-408 ◽  
Author(s):  
Kenichi Kazuki ◽  
Masataka Kusunoki ◽  
Akira Shimazu
Keyword(s):  
Pressure Distribution ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Radiocarpal Joint ◽  
Pressure Sensitive Film

The Use of Contact Biomechanics to Study the Intact, Proximal Row Carpectomy and Scaphoid Excision, Four Bone Fusion Wrist

2020 ◽  
Vol 16 (3) ◽  
pp. 189-193
Author(s):  
David H. Wei ◽  
Peter Tang
Keyword(s):  
Proximal Row Carpectomy ◽  
Scapholunate Ligament ◽  
Bone Fusion ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Radiocarpal Joint ◽  
Pressure Sensitive Film ◽  
Number Of Authors

The study of contact biomechanics of the wrist is a challenge. This is partly due to the relatively small size of the joint as well as the lack of space in the radiocarpal joint which makes the delivery of investigative materials such as pressure sensitive film without causing artifact, difficult. Fortunately, a number of authors have studied the intact wrist, the scapholunate ligament injured wrist, the proximal row carpectomy and the scaphoid excision, four bone fusion. Despite some contrasting findings, there are some general concepts that we understand about wrist mechanics.

A Technique for Measuring Absolute Toe Pressures: Evaluation of Pressure-Sensitive Film Techniques

Foot & Ankle ◽  
1992 ◽  
Vol 13 (4) ◽  
pp. 220-223 ◽  
Author(s):  
Alan S. Tuckman ◽  
Frederick W. Werner ◽  
Maria D. Fortino ◽  
Joseph A. Spadaro
Keyword(s):  
Soft Tissues ◽  
Flat Surface ◽  
Imaging System ◽  
Accurate Method ◽  
Total Force ◽  
Confined Space ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Pressure Sensitive Film ◽  
Deforming Forces

Although a number of pathologies of the forefoot in ballet dancers on pointe have been described, pressures and deforming forces have not been adequately measured. To evaluate the possible use of pressure-sensitive film (PSF) in measuring the pressures on the external soft tissues in such a confined space as the dancer's toe shoe, it was tested and calibrated with 20 cadaver toes. Each cadaver toe was internally stabilized and loaded longitudinally against PSF on a flat surface. The resultant films were analyzed with a video imaging system and the pressures and total forces were determined. Results showed that the linearity of the PSF to pressure had a regression value of 0.98. By using two sensitivity ranges of films, the total force measured by the PSF was found to be within 10% of the known applied force on each toe. The PSF, therefore, may very well be a useful and accurate method of measuring external soft tissue pressures on the forefoot.

Biomechanics of the wrist after proximal row carpectomy in cadavers

2009 ◽  
Vol 35 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Y.-L. Zhu ◽  
Y.-Q. Xu ◽  
J. Ding ◽  
J. Li ◽  
B. Chen ◽  
...  
Keyword(s):  
Sharp Decrease ◽  
Material Testing ◽  
Testing System ◽  
Average Pressure ◽  
Proximal Row Carpectomy ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Fresh Frozen ◽  
Pressure Sensitive Film ◽  
Lunate Fossa

We investigated the biomechanics of the radiocapitate joint after a proximal row carpectomy in six fresh-frozen cadaver wrists using super-low-pressure-sensitive film on a material testing system. The average pressure within the lunate fossa increased significantly from 23.2 to 136.4 N/cm2 with a sharp decrease in the contact area from 2.08 to 0.30 cm2 after a proximal row carpectomy. The cartilage of the proximal capitate had four sub-facets and therefore was not as smooth as the normal proximal lunate. We found that the wrist was overloaded after a proximal row carpectomy and the main cause was the anatomical mismatch of the radiocapitate articulation.

Contact Stress and Linearized Modal Predictions of As-Built Preloaded Assembly

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Adam R. Brink ◽  
Robert J. Kuether ◽  
Matthew D. Fronk ◽  
Bryan L. Witt ◽  
Brendan L. Nation
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Contact Area ◽  
Element Model ◽  
High Fidelity ◽  
Vibration Modes ◽  
Low Level ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Pressure Sensitive Film

Abstract The member stiffness and pressure distribution in a bolted joint is significantly influenced by the contact area of the mechanical interface under a prescribed preload force. This research explores the influence of as-built surface profiles for nominally flat interfaces of a C-Beam assembly with two well-defined contact regions. A high-fidelity finite element model is created such that the model uncertainty is minimized by updating and calibrating the piece parts prior to the preload assembly procedure. The model is then assembled and preloaded to evaluate the contact stresses and contact area for both nominally flat and perturbed non-flat surfaces based on three-dimensional surface topography measurements. The predicted pressures are validated with digitized pressure-sensitive film measurements. The high-fidelity modeling reveals how the compliance and thickness of the pressure-sensitive film alter the measured pressures, leading to incorrect evaluations of the stresses and contact area in the joint. The resulting low-level dynamic behavior of the preloaded assembly is shown to be sensitive to the true contact area by linearizing the nonlinear finite element model about the preloaded equilibrium and performing a computational modal analysis. The resonant frequencies are validated with experimental measurements to demonstrate the effect of the contact area on the modal characteristics of the bolted assembly. Vibration modes and loading patterns exhibit varying levels of sensitivity to the contact area in the joint, leading to an improved physical understanding of the influence of contact mechanics on the low-level linear vibration modes of jointed assemblies.

Wheel-Rail Contact Patch Geometry Measurement and Shape Analysis Under Various Loading Conditions

2020 ◽  
Author(s):  
Ahmad Radmehr ◽  
Arash Hosseinian Ahangarnejad ◽  
Yu Pan ◽  
SayedMohammad Hosseini ◽  
Ali Tajaddini ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Wheel Load ◽  
Contact Patch ◽  
Pressure Sensitive ◽  
Sensitive Film ◽  
Consistent Method ◽  
Geometry Measurement ◽  
Static Conditions ◽  
The Relationship ◽  
Patch Geometry

Abstract This study evaluates the wheel-rail contact patch geometry of the VT-FRA roller rig, designed and commissioned at the Virginia Tech’s Railway Technologies Laboratory (RTL). Contact patch measurements are crucial for better analyzing the underlying factors that affect the wheel-rail interface (WRI) contact mechanics and dynamics. One of the challenges is in determining the size and pressure distribution at the contact patch, under various conditions. Although past studies have attempted to reach a method that can be used to make such measurements, more research is needed in reaching a practical and consistent method. This is particularly true for making the measurements under dynamic conditions. The use of pressure sensitive films was considered as the means for contact patch measurements on the VT-FRA rig, however, the thickness of the film influences the contact patch area and shape. This paper provides the results of the measurements with films with different range of pressure sensitivities. Three types of pressure-sensitive films are used under static conditions. The films are placed in between the wheel and roller in exact positions to enable comparing the test results for various wheel loads. The contact patch measured by the most sensitive film, which reacts to pressures as low as 0.5 MPa, provides the most accurate outline for the contact patch, although it does not provide the highest resolution for the pressure distribution. The other pressure-sensitive films that are used have a higher pressure range, with minimums of 49.0 MPa and 127.6 MPa. The relationship between the size of the contact patch and average contact pressure is evaluated as a function of the wheel load. The results indicate that with increasing wheel load, the size of the contact patch changes minimally, with the average pressure increasing in a nearly linear relationship to the wheel load as expected.

Use of Pressure-Sensitive Film to Quantify Sources of Injury to Fish

2005 ◽  
Vol 25 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Glenn Čada ◽  
John Smith ◽  
Jessica Busey
Keyword(s):  
Pressure Sensitive ◽  
Sensitive Film ◽  
Pressure Sensitive Film
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