Load-Bearing Capacity of Functioning Alumina Dental Endosseous Implants

1976 ◽  
Vol 55 (1) ◽  
pp. 22-29 ◽  
Author(s):  
S.H. Wolfson ◽  
G.W. Svare ◽  
D. Weber

Ten, solid, 99.7% Al 2O3 implants were sur'gically placed bilaterally in the mandibles of Rhesus monkeys and were then placed in function after two to four weeks. After 95 to 179 days, bone blocks were surgically removed. Load-bearing capacity of the six successful implants was determined as the maximum load that did not produce plastic deformation. The average of this value was 57.5 kg. Histological examination showed excellent bone-implant compatibility.

2013 ◽  
Vol 644 ◽  
pp. 175-178
Author(s):  
Jing Ping Wei ◽  
Fan Chen ◽  
Zhi Hao Ding

Through the floor specific pressure test, the floor specific pressure was obtained. The rock mass of mudstone, under the loading perpendicular to the weak plane, was in brittle-plastic failure state, and the bearing capacity of mudstone was equal to the Ⅲa grade floor. The brittle-plastic transition mechanism of the mudstone was revealed: Firstly, the more size, the more heterogeneity. The mudstone body was bigger than its rock samples, so there were more planes of weakness, which caused the macroscopic plastic deformation. Secondly, the directions of the load and the weak plane influenced the strength of the mudstone floor. During the plastic deformation, the compressive failure occurred layer by layer under the loading perpendicular to the weak planes, and the post peak load-bearing capacity of mudstone floor was decided by the layer’s strength.


2018 ◽  
Vol 763 ◽  
pp. 235-242
Author(s):  
Iathong Chan ◽  
Yuji Koetaka

Steel moment frames are designed to ensure sufficient energy absorption capacity by achieving an entire beam-hinging collapse mechanism against severe earthquakes. Therefore, the column overdesign factor is stipulated in seismic design codes in some countries. For example in Japanese seismic design code, the specified column overdesign factor is 1.5 or more for steel moment frames with square tube columns. And this paper describes seismic response by 3D analysis of steel moment frames, and presents seismic demand for the column overdesign factor to keep the damage of square tube columns below the specified limit of plastic deformation. The major parameters are column overdesign factor, horizontal load bearing capacity, shape of frames and input direction of ground motion. In order to investigate 3D behavior of frames and correlation between plastic deformation of columns and column over design factor, apparent column overdesign factor, which is defined as the ratio of full plastic moment of the column (s) to the full plastic moment of the beam (s) projected in the input direction of the ground motion, is introduced. From the earthquake response analysis, it is clarified that the profile of maximum value of cumulative plastic deformation of columns to apparent column overdesign factor, with the similar horizontal load bearing capacity, are nearly identical regardless of number of stories, floor plan, and input direction of ground motion. As a result, the required column overdesign factor to keep the damage of columns below the limit of plastic deformation is proposed under the reliability index of 2.


2015 ◽  
Vol 660 ◽  
pp. 208-212 ◽  
Author(s):  
Mihai Fofiu ◽  
Andrei Bindean ◽  
Valeriu Stoian

This paper presents the retrofitting procedure used on a precast reinforced concrete wall panel (PRCWP) in order to restore its initial load bearing capacity. The specimen used in this experimental test is one from the residential multistoried buildings constructed in Romania from the 1970 onwards. All of the characteristics of the element are from the specific era, only scaled down with a factor of 1:1,2. The element was subjected to in-plane reversed cyclic loading to simulate its seismic behavior and obtain its maximum load bearing capacity. After the test we retrofitted the element using Carbon Fiber Strips Externally Bonded (EBR) and anchored with Carbon Fiber Reinforced Polymers (CFRP) mesh. The porpoise of the paper is to compare the maximum loading bearing capacity of the unstrengthen and strengthen elements in order to compare them and examine the efficiency of this retrofitting procedure.


Author(s):  
Aleksandr Starov ◽  
Sergei Kalashnikov

The finiterelationship between the forces and moments of plates and shells in the parametric form of the theory of small elastoplastic deformations is investigated of A.A. Ilyushin, to determine the load-bearing capacity of structures from a material without hardening. A geometric image of the exact yield surface in the space of generalized stresses is obtained. In the firstpart of the article the conclusion of the finalrelation is given. In the second and third parts, by introducing other parameters, alternative equivalent dependences of the finalrelationship have been developed and variants of its approximation for application in computational practice are considered. In the fourth part, additional properties of the finalrelationship are considered, the possibility and necessity of its use in problems of plastic deformation of plates and shells is shown.


2012 ◽  
Vol 12 (01) ◽  
pp. 153-178 ◽  
Author(s):  
PENG FENG ◽  
SAWULET BEKEY ◽  
YAN-HUA ZHANG ◽  
LIE-PING YE ◽  
YU BAI

Fiber-reinforced polymer (FRP) strengthening technique to improve buckling resistance of steel members is presented in concept and experimental demonstration. The conceptual design of this method is introduced through the preliminary experiments on three specimens. Then, another 14 specimens are tested under axially compressive loading, by which the compressive behavior and the strengthening effects are investigated considering different design parameters and configuration, including the slenderness ratio, the confinement detail, the filled materials and the end connection. The strengthening effects are analyzed by the comparison of both theoretical and test results, which show that the overall buckling failure of steel members can be prevented by FRP strengthening and the ultimate loading capacity and deformation capacity of steel members are enhanced considerably. The maximum load-bearing capacity of strengthened members is 2.86 times of the nonstrengthened ones, and the failure maintains a ductile behavior. In addition, the load-bearing capacity of the members strengthened in this way is compared with the Euler loads of the original steel member and the composite member.


2020 ◽  
Vol 404 ◽  
pp. 3-10
Author(s):  
Sebastian Wiesenmayer ◽  
Marion Merklein

Shear-clinching allows the joining by forming of dissimilar materials with high differences between their mechanical properties without additional fasteners. Since the lower joining partner is indirectly shear cut during the process, even ultra-high strength materials can be joined. However, the cutting of the high-strength materials as well as the extrusion of the upper joining partner leads to high process forces and therefore to high tool loads. This applies in particular for the die, which is highly stressed during the cutting phase and therefore plastically deformed. Within the scope of this work, the influence of the occurring wear on the formation of the joint and its load-bearing capacity is analyzed for a scope of 500 strokes. For this purpose, press hardened 22MnB5 is used as lower joining partner. Its high strength leads to the plastic deformation of the cutting edge, which increases within the first 200 strokes. Afterwards only minor changes occur. Yet, no effect of the occurring wear on the joint formation and the joint strength, which was tested under shear and tensile load, could be determined. Functioning joints could still be produced for more than 500 strokes as the load-bearing capacity remained on a comparable level.


2017 ◽  
Vol 15 (4) ◽  
pp. e356-e361 ◽  
Author(s):  
Jaakko M. Piitulainen ◽  
Riina Mattila ◽  
Niko Moritz ◽  
Pekka K. Vallittu

Background Glass fiber-reinforced composites (FRCs) have been adapted for routine clinical use in various dental restorations and are presently also used in cranial implants. The aim of this study was to measure the load-bearing capacity and failure type of glass FRC implants during static loading with and without interconnective bars and with different fixation modes. Methods Load-bearing capacities of 2 types of FRC implants with 4 different fixation modes were experimentally tested. The sandwich-like FRC implants were made of 2 sheets of woven FRC fabric, which consisted of silanized, woven E-glass fiber fabrics impregnated in BisGMA-TEGDMA monomer resin matrix. The space between the outer and inner surfaces was filled with glass particles. All FRC implants were tested up to a 10-mm deflection with load-bearing capacity determined at 6-mm deflection. The experimental groups were compared using non-parametric Kruskal-Wallis analysis with Steel-Dwass post hoc test. Results FRC implants underwent elastic and plastic deformation until 6-mm deflection. The loading test did not demonstrate any protrusions of glass fibers or cut fiber even at 10-mm deflection. An elastic and plastic deformation of the implant occurred until the FRC sheets were separated from each other. In the cases of the freestanding setup (no fixation) and the fixation with 6 screws, the FRC implants with 2 interconnective bars showed a significantly higher load-bearing capacity compared with the implant without interconnective bars. Conclusions FRC implants used in this study showed a load-bearing capacity which may provide protection for the brain after cranial bone defect reconstruction.


2018 ◽  
Vol 234 ◽  
pp. 04002 ◽  
Author(s):  
Glib Vatulia ◽  
Yevhen Orel ◽  
Maryna Rezunenko ◽  
Nataliia Panchenko

In the current practice of construction and design of transport facilities, structures with external reinforcement are commonly used which effectively resist compression. The use of steel-concrete and composite structures enables us to reduce material consumption and cost of structures significantly. There are a few established approaches used to evaluate the load-bearing capacity of steel-concrete structures under axial and eccentric compression, each being based on the initial prerequisites, which underlie the calculation formulas. In this paper, the functional relationship of the value of the maximum load-bearing capacity of rectangular concrete-filled steel tubular (CFST) columns under axial compression with the random eccentricity is plotted. A regression model is proposed based on the methods of mathematical statistics, which allows for the evaluation of the impact of geometrical and physical characteristics of rectangular CFST columns on the value of their load-bearing capacity. The correspondence of the obtained model to the experimental data, as well as the significance of the regression parameters are confirmed by Fisher and Student criteria.


2022 ◽  
Vol 1048 ◽  
pp. 254-260
Author(s):  
Kaushik V. Prasad ◽  
H. Adarsha

Al2O3, Al2O3-10%CeO2 and Al2O3 – 20% CeO2 coatings were deposited on Mg AZ91 alloy by High Velocity Oxy Fuel (HVOF) process. The microstructure of deposited coatings was characterized by scanning electron microscopy and x-ray diffraction. Nano-indentation tests were performed on deposited coatings to determine its load bearing capacity and elastic recovery. Al2O3 coatings exhibited coarse grain structure with porous sites. While addition of CeO2 promoted grain refinement in the coatings. A load of 100mN was applied on all the samples for nano-indentation test. Coating with 20%CeO2 exhibited maximum load bearing capacity of 98.7mN with elastic recovery displacement of 1000 nm.


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