Plastics. Determination of compressive properties

2015 ◽  
2013 ◽  
Vol 2013 (0) ◽  
pp. _OS0704-1_-_OS0704-2_
Author(s):  
Masahiro NISHIDA ◽  
Yoshitaka ITO ◽  
Tesuo TAKAYAMA ◽  
Mitsugu TODO ◽  
Gustaf GUSTAFSSON ◽  
...  

2000 ◽  
Vol 123 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Mark E. Zobitz ◽  
Zong-Ping Luo ◽  
Kai-Nan An

A methodology was developed for determining the compressive properties of the supraspinatus tendon, based on finite element principles. Simplified three-dimensional models were created based on anatomical thickness measurements of unloaded supraspinatus tendons over 15 points. The tendon material was characterized as a composite structure of longitudinally arranged collagen fibers within an extrafibrillar matrix. The matrix was formulated as a hyperelastic material described by the Ogden form of the strain energy potential. The hyperelastic material parameters were parametrically manipulated until the analytical load-displacement results were similar to the results obtained from indentation testing. In the geometrically averaged tendon, the average ratio of experimental to theoretical maximum indentation displacement was 1.00 (SD: 0.01). The average normalization of residuals was 2.1g (SD: 0.9g). Therefore, the compressive material properties of the supraspinatus tendon extrafibrillar matrix were adequately derived with a first-order hyperelastic formulation. The initial compressive elastic modulus ranged from 0.024 to 0.090 MPa over the tendon surface and increased nonlinearly with additional compression. Using these material properties, the stresses induced during acromional impingement can be analyzed.


1958 ◽  
Vol 57 (4) ◽  
pp. 487-495 ◽  
Author(s):  
John W. Stanford ◽  
G.C. Paffenbarger ◽  
John W. Kumpula ◽  
W.T. Sweeney

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2717
Author(s):  
Rebeka Rudolf ◽  
Danica Popović ◽  
Sergej Tomić ◽  
Rajko Bobovnik ◽  
Vojkan Lazić ◽  
...  

In this research work, we synthesised poly(methyl methacrylate) (PMMA) enriched with 2 wt.% zinc oxide nanoparticles (ZnO) through conventional heat polymerisation and characterised its microstructure. It was found that the distribution of ZnO nanoparticles was homogeneous through the volume of the PMMA. The mechanical testing of the PMMA-ZnO composite primarily included the determination of the compressive properties on real dentures, while density measurements were performed using a pycnometer. The testing of functional properties involved the identification of the colour of the new PMMA-ZnO composite, where pure PMMA acted as a control. In the second step, the PMMA-ZnO cytotoxicity assays were measured in vitro, which were shown to be similar to the control PMMA. Based on this, it could be concluded that the newly formed PMMA-ZnO composite did not induce direct or indirect cytotoxic effects in L929 cell cultures; therefore, according to ISO/DIN 10993-5:2009, this composite was categorised as non-cytotoxic.


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