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  • 1
    Electronic Resource
    Electronic Resource
    Axi-symmetric bodies of equal material in contact under torsion or shift (1995)
    Springer
    Archive of applied mechanics 65 (1995), S. 478-487 
    Details
    ISSN: 1432-0681
    Keywords: Key words Contact problem of elasticity ; superposition ; flat punch solutions ; annular sliding ; stick area.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary  Two axi-symmetric bodies are pressed together, so that their axes of symmetry coincide with the contact normal and the normal force is held constant. A small torque about the contact normal or a small tangential force is applied. For bodies of equal material, the normal and tangential stress states are uncoupled, and can be solved separately. The surfaces of the bodies are thought as a superposition of infinitesimal rigid flat-ended punches. Consequently, the normal stress distribution can be calculated as a summation of differential flat punch solutions. A formula results, which is identical with the solution of Green and Collins. After application of a torque an annular sliding area forms at the border of the contact area. For reasons of symmetry, the common displacement of the inner stick area must be a rigid body rotation. Similarly to the normal problem, the solution can be thought as a superposition of rigid punch rotations. The tangential solution can be derived analogically, in form of a superposition of rigid punch displacements. The present method also solves the problem of simultaneous normal and torsional or tangential loading with complete adhesion. As an example, Steuermann’s problem for polynomial surfaces of the form A 2 n r2 n is solved. The solutions for constant normal forces can be used as basic functions for loading histories with varying normal and tangential forces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00835661
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Axi-symmetric bodies of equal material in contact under torsion or shift (1995)
    Springer
    Archive of applied mechanics 65 (1995), S. 478-487 
    Details
    ISSN: 1432-0681
    Keywords: Contact problem of elasticity ; superposition ; flat punch solutions ; annular sliding ; stick area
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Two axi-symmetric bodies are pressed together, so that their axes of symmetry coincide with the contact normal and the normal force is held constant. A small torque about the contact normal or a small tangential force is applied. For bodies of equal material, the normal and tangential stress states are uncoupled, and can solved separately. The surfaces of the bodies are thought as a superposition of infinitesimal rigid flat-ended punches. Consequently, the normal stress distribution can be calculated as a summation of differential flat punch solutions. A formula results, which is identical with the solution of Green and Collins. After application of a torque an annular sliding area forms at the border of the contact area. For reasons of symmetry, the common displacement of the inner stick area must be a rigid body rotation. Similarly to the normal problem, the solution can be thought as a superposition of rigid punch rotations. The tangential solution can be derived analogically, in form of a superposition of rigid punch displacements. The present method also solves the problem of simultanous normal and torsional or tangential loading with complete adhesion. As an example, Steuermann's problem for polynomial surfaces of the formA 2nr2nis solved. The solutions for constant normal forces can be used as basic functions for loading histories with varying normal and tangential forces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00835661
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Les patella douloureuses non instables Opération de Maquet (1994)
    Springer
    European journal of orthopaedic surgery & traumatology 4 (1994), S. 201-203 
    Details
    ISSN: 1432-1068
    Keywords: Knee ; Patello-femoral pain ; Maquet procedure ; Genou ; Chondropathie fémoro-patellaire ; Opération de Maquet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'intervention de Maquet réalise une avancée de la tubérosité tibiale antérieure et donc de l'insertion du ligament patellaire (tendon rotulien). Ceci a pour conséquence mécanique une diminution des pressions exercées sur le cartilage fémoro-patellaire, qui a été prouvée expérimentalement par les travaux de Ferguson et Wagner. La technique actuellement préconisée découpe une longue baguette tibiale et réalise une avancée de l'ordre du centimètre, avec greffon prélevé localement plutôt que sur la crête iliaque et ostéosynthèse par vis permettant la mobilisation immédiate. Une série de 124 patients a été suivie avec un recul moyen de 5 ans (extrêmes de 1 à 8 ans). Le résultat objectif est satisfaisant dans 57 % des cas, avec un taux d'échec de 17 %. Le résultat subjectif, toujours meilleur, est satisfaisant dans 77 % des cas, avec un taux d'échec de 16 %. L'analyse statistique des facteurs pronostiques donne une valeur péjorative aux atteintes cartilagineuses macroscopiques modérées, sans mise à nu de l'os sous-chondral, et souligne l'intérêt des gestes thérapeutiques directs sur le cartilage, en particulier lorsque l'os sous-chondral est à nu. La revue de la littérature retrouve des résultats comparables en valeurs absolues ; le rôle pronostique de l'importance des lésions chondrales est diversement apprécié, alors que celui des gestes directs sur le cartilage n'est guère étudié.
    Notes: Summary Advancement of the tibial tubercle and patellar ligament reduces the patello-femoral contact forces, which has been experimentally proved by Ferguson and Wagner. The authors have chosen the modified original technique described by Maquet, who performs a frontal osteotomy of the tibial tubercle with advancement about 1 cm, local or iliac bone graft and screw fixation to allow early mobilization. 124 patients were followed during 1–8 years. Overall objective results are satisfactory in 57% of cases, with a failure rate of 17%. Subjective results are always better : 77% of patients are satisfied and only 16% disappointed with their functional result. Statistical analysis shows that results are better when subchondral bone is eburnated, and when direct treatment of osteochondral lesions is performed. Others series already published in the litterature show comparable figures. The influence of the grade of chondral lesions is not accepted by all authors. The role of osteochondral treatment is not studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02115911
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Elevation of the tibial tubercle for patellofemoral pain syndrome (1996)
    Springer
    Knee surgery, sports traumatology, arthroscopy 4 (1996), S. 92-96 
    Details
    ISSN: 1433-7347
    Keywords: Patellofemoral pain ; Maquet procedure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Sports Science
    Description / Table of Contents: Resumé 100 patients opérés d'un avancement de la tubérosité tibiale antéricure selon Maquet ont été réexaminés avec un recul moyen de quatre ans, et 65 d'entre cux ont pu être réexaminés ultérieurement avec un recul moyen de onze ans (extrêmes de huit à quinze ans). L'intensité de la douleur a été significativement diminuée après l'intervention et cette amélioration est restée stable dans le temps. Mais globalement le taux de succès n'était que de 62% à chacun des deux examens. La présence à l'intervention d'une mise à nu de l'os sous-chondral était significativement associée à un meilleur résultat antalgique, avec un taux de succès de 69%. L'intervention de Maquet ne doit être proposée que pour un syndrome douloureux fémoropatellaire avec mise à nu de l'os sous-chondral, mais l'indication doit être prudente car le taux d'échec est élevé.
    Notes: Abstract One hundred patients were operated on by the Maquet procedure for chondromalacia patellae. All of them were first re-examined after a mean follow-up of 4 years, and 65 of them re-examined after a mean follow-up of 11 years (range, 8–15 years). The pain score improved significantly after the operation and remained unchanged with longer follow-up. The success rate was only 62% at both follow-ups. Outerbridge grade IV chondral lesions at the time of surgery were associated with a significant improvement of the pain score at the 4-year follow-up and a success rate of 69%. The Maquet procedure should only be proposed for chronic retropatellar pain with grade IV chondral lesions. after conservative treatment has proven unsuccessful, as the expected failure rate is about 30%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01477260
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    Paper (German National Licenses)
    Fulltext
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