Reconstruction of the interosseous ligament restores normal forearm compressive load transfer in cadavers

2005 ◽  
Vol 30 (2) ◽  
pp. 319-325 ◽  
Author(s):  
H. James Pfaeffle ◽  
Kathryne J. Stabile ◽  
Zong-Ming Li ◽  
Matthew M. Tomaino
2000 ◽  
Vol 37 (1) ◽  
pp. 56-74 ◽  
Author(s):  
M Hesham El Naggar ◽  
Jin Qi Wei

Tapered piles have a substantial advantage with regard to their load-carrying capacity in the downward frictional mode. The uplift performance of tapered piles, however, has not been fully understood. This paper describes the results of an experimental investigation into the characteristics of the uplift performance of tapered piles. Three instrumented steel piles with different degrees of taper were installed in cohesionless soil and subjected to compressive and tensile load tests. The soil was contained in a steel soil chamber and pressurized using an air bladder to facilitate modelling the confining pressures pertinent to larger embedment depths. The results of this study indicated that the pile axial uplift capacity increased with an increase in the confining pressure for all piles examined in this study. The ratios of uplift to compressive load for tapered piles were less than those for straight piles of the same length and average embedded diameter. The uplift capacity of tapered piles was found to be comparable to that of straight-sided wall piles at higher confining pressure values, suggesting that the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles. Also, the results indicated that residual stresses developed during the compressive loading phase and their effect were more significant on the initial uplift capacity of piles, and this effect was more pronounced for tapered piles in medium-dense sand.Key words: tapered piles, uplift, axial response, load transfer, experimental modelling.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7173
Author(s):  
Tomasz Derda ◽  
Zbigniew Domanski

When a multicomponent system is suddenly loaded, its capability of bearing the load depends not only on the strength of components but also on how a load released by a failed component is distributed among the remaining intact ones. Specifically, we consider an array of pillars which are located on a flat substrate and subjected to an impulsive and compressive load. Immediately after the loading, the pillars whose strengths are below the load magnitude crash. Then, loads released by these crashed pillars are transferred to and assimilated by the intact ones according to a load-sharing rule which reflects the mechanical properties of the pillars and the substrate. A sequence of bursts involving crashes and load transfers either destroys all the pillars or drives the array to a stable configuration when a smaller number of pillars sustain the applied load. By employing a fibre bundle model framework, we numerically study how the array integrity depends on sudden loading amplitudes, randomly distributed pillar strength thresholds and varying ranges of load transfer. Based on the simulation, we estimate the survivability of arrays of pillars defined as the probability of sustaining the applied load despite numerous damaged pillars. It is found that the resulting survival functions are accurately fitted by the family of complementary cumulative skew-normal distributions.


2019 ◽  
Vol 9 (3) ◽  
pp. 17-21
Author(s):  
Vladimir P. SELYAEV ◽  
Nikolay N. KISELEV ◽  
Oleg V. LIYASKIN

The possibility of using vacuum insulation panels (VIP) with a granular filler for the manufacture of threelayer enclosing wall panels, floor slabs and coatings is considered. The results of experimental studies of vacuum insulation panels, carried out with the aim of analytically describing the deformation diagrams of VIP panels under the action of a compressive load, are presented. It has been established: deformative properties of vacuum insulation panels with granular filler do not depend on the size of the filler particles, but depend on the volume content of the filler; a deformation diagram describing the relationship between stresses and relative deformations during compression of a vacuum insulating panel with a granular filler can be approximated by the function G. B. Bülfinger. The results obtained make it possible by calculation to determine the stress state in flat plating sheets during local load transfer.


2012 ◽  
Vol 178-181 ◽  
pp. 1550-1554 ◽  
Author(s):  
Bao Tao Huang ◽  
Ding Liu ◽  
Fang Wang ◽  
Jie Li

In this paper, the caustics method was used to explore the distribution of contact forces inside a packing of discrete square cells submitted to a compressive load. The self making subroutine 3-D generation algorithm about irregular particle generation and particle contact interface generation were adopted, and irregular particles were randomly generated in the designated categories with this algorithm. The vibration compacting load diffuse and transfer law with different media dense state were analyzed. The test results show that the vibration load caused the effective compaction region was changed vertical long axis oval into the level long axis oval. The study provides an idea to research and employs a new over-loading road which better repels tired retrogression under the dynamic load.


2012 ◽  
Vol 25 (04) ◽  
pp. 286-296 ◽  
Author(s):  
P. DeVasConCellos ◽  
V. K. Balla ◽  
S. Bose ◽  
R. Fugazzi ◽  
W. S. Dernell ◽  
...  

SummaryObjectives: To design, manufacture and analyze custom implants with functional gradation in macrostructure for attachment of amputation prostheses.Methods: The external shape of the implant was designed by extracting geometrical data of canine cadavers from computed tomography (CT) scans to suit the bone cavity. Three generations of implant designs were developed and were optimized with the help of fit/fill and mechanical performance of implant-cadaver bone assembly using CT analysis and compression testing, respectively. A final optimized, custom Ti6Al4V alloy amputation implant, with approximately 25% porosity in the proximal region and approximaltely zero percent porosity in the distal region, was fabricated using Laser Engineered Net Shaping (LENS™) – a laser based additive manufacturing technology.Results: The proposed design changes in the second generation designs, in terms of refining thresholds, increased the average fill of the bone cavity from 58% to 83%. Addition of a flange between the stem and the head in the second generation designs resulted in more than a seven-fold increase in the compressive load carrying capacity of the assembly. Application of LENS™ in the fabrication of present custom fit Ti6Al4V alloy implants enabled incorporation of 20 to 30% porosity in the proximal region and one to two percent residual porosity in the distal portion of the implant.Clinical significance: Patient specific prostheses having direct connection to the skeletal structure can potentially aid in problems related to load transfer and proprioception in amputees. Furthermore, application of LENS™ in the fabrication of custom implants can be faster to incorporate site specific porosity and gradients for improving long-term stability.


2003 ◽  
Vol 28 (3) ◽  
pp. 267-270 ◽  
Author(s):  
MATTHEW M. TOMAINO ◽  
JAMIE PFAEFFLE ◽  
KATHRYNE STABILE ◽  
ZONG-MING LI

Excision of the radial head after fracture may be complicated by longitudinal radio-ulnar instability (Essex-Lopresti lesion) if the forearm interosseous ligament has also been torn. In such cases proximal migration of the radius occurs, and ulnar impaction at the wrist and radiocapitellar contact at the elbow may impair function. Although metal radial head arthroplasties are now used for irreparable radial head fractures, the long-term clinical outcome may still be unsatisfactory because of excessive radiocapitellar load causing pain. Interosseous ligament reconstruction might improve outcome by restoring normal load transfer from the radius to ulna, but the biomechanical effect of reconstruction has not been reported. This study evaluated forearm load transfer following interosseous ligament reconstruction with an Achilles tendon allograft in a cadaveric model with the radial head intact. Interosseous ligament reconstruction reduced proximal radius loading by transferring force to the proximal ulna, but force transfer by the reconstruction was only half that by the intact ligament.


MRS Advances ◽  
2021 ◽  
Author(s):  
Shreyas Srivatsa ◽  
Pawel Packo ◽  
Leon Mishnaevsky ◽  
Tadeusz Uhl ◽  
Krzysztof Grabowski

AbstractA new two-dimensional nanomaterial—Titanium Carbide MXene (Ti3C2-MXene)—was reported in 2011. In this work, the microscale models of Ti3C2-MXene nanomaterial are considered with polymer matrix. The nanocomposites are modeled using nacre-mimetic brick-and-mortar assembly configurations due to enhanced mechanical properties and interlocking mechanism between the Ti3C2-MXene (brick) and polymer matrices (mortar). The polymer matrix material (Epoxy-resin) is modeled with elastic and viscoelastic behavior (Kelvin–Voigt Model). The Finite Element Method is used for numerical analysis of the microscale models with the multi-point constraint method to include Ti3C2-MXene fillers in the polymer matrix. Ti3C2-MXenes are considered as thick plate elements with transverse shear effects. The response of elastic and viscoelastic models of polymer matrix are studied. Finally, a tensile and compressive load is applied at the microscale and the effective load transfer due to nacre-mimetic configuration is discussed. This paper provides nacre-mimetic models to pre-design the nanocomposite for optimal performance with damage resistance and enhanced strength.


Author(s):  
Jan-Peter Grunz ◽  
Carsten Herbert Gietzen ◽  
Katharina Grunz ◽  
Thorsten Bley ◽  
Rainer Schmitt

Background The term “carpal instability” describes different debilitating wrist conditions, in which the carpus is unable to maintain its physiological range of motion and load transfer. Depending on the cause and location of the dysfunction, four groups can be defined: dissociative, non-dissociative, complex, and adaptive carpal instability. As the most common form by far, dissociative carpal instability can further be categorized as dorsal or palmar intercalated segment instability, contingent on the afflicted interosseous ligament. Method This review article outlines the different entities of carpal instability, their pathophysiology, and their clinical presentation. It further discusses the diagnostic significance of different imaging methods as well as the established treatment options for each form of instability in context with the current literature. Results and Conclusion Early detection and treatment of carpal instability are essential for preventing carpal osteoarthritis. Traumatic lesions of the scapholunate interosseous ligament are the most frequent cause of instability. They can occur in an isolated fashion or in context with other carpal injuries. While stress imaging and fluoroscopy facilitate the differentiation between dynamic and static forms of carpal instability, only MRI and CT/MR arthrography can directly reveal the extent of ligament discontinuity. Key Points: Citation Format


2000 ◽  
Vol 25 (4) ◽  
pp. 683-688 ◽  
Author(s):  
H.James Pfaeffle ◽  
Kenneth J. Fischer ◽  
Theodore T. Manson ◽  
Matthew M. Tomaino ◽  
Savio L-Y. Woo ◽  
...  

Author(s):  
Shreyas Srivatsa ◽  
Pawel Packo ◽  
Leon Mishnaevsky Jr. ◽  
Tadeusz Uhl ◽  
Krzysztof Grabowski

A new two-dimensional nanomaterial – Titanium Carbide MXene (Ti3C2-MXene) – was reported in 2011. In this work, the microscale models of Ti3C2-MXene nanomaterial are considered with polymer matrix. The nanocomposites are modeled using nacre-mimetic brick-and-mortar assembly configurations due to enhanced mechanical properties and interlocking mechanism between the Ti3C2-MXene (brick) and polymer matrices (mortar). The polymer matrix material (Epoxy-resin) is modeled with elastic and viscoelastic behavior (Kelvin-Voigt Model). The Finite Element Method is used for numerical analysis of the microscale models with the multi-point constraint method to include Ti3C2-MXene fillers in the polymer matrix. Ti3C2-MXenes are considered as thick plate elements with transverse shear effects. The response of elastic and viscoelastic models of polymer matrix are studied. Finally, a tensile and compressive load is applied at the microscale and the effective load transfer due to nacre-mimetic configuration is discussed. This paper provides nacre-mimetic models to pre-design the nanocomposite for optimal performance with damage resistance and enhanced strength.


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