Advanced Surface Mechanical Testing of Materials for Medical Applications

2009 ◽  
Author(s):  
Ethel Poire´
Keyword(s):  
Mechanical Testing ◽  
Single Point ◽  
Thin Layers ◽  
Medical Applications ◽  
Indentation Testing ◽  
Instrumented Indentation ◽  
Scratch Testing ◽  
Elastic Materials ◽  
Optical Contrast ◽  
Testing Techniques

This paper presents an overview of two advanced surface mechanical testing techniques: the instrumented indentation testing and the single point scratch testing techniques. Both can be used for studying bulk or thick materials, they are however powerful tools in the cases of thin layers and small features, elastic materials and surfaces with poor optical contrast. Most samples can be tested “as is” or with minimal preparation.

Finite Element Analysis of Fiber Composite Dental Bridges: The Effect of Length / Depth Ratio and Load Application Method

1999 ◽  
Author(s):  
Michael D. Nowak ◽  
Kim Haser ◽  
A. Jon Goldberg
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Testing ◽  
Fiber Composite ◽  
Single Point ◽  
Element Analysis ◽  
Elastic Range ◽  
Single Force ◽  
Range Testing ◽  
Fiber Reinforce

Abstract Work is continuing in the evaluation of orthotropic fiber reinforce composites for use in the construction of dental bridges. Finite Element Analysis (FEA) models were constructed based upon mechanical testing of end clamped specimens center loaded with a metal indenter. Various length / depth specimens were evaluated in the elastic range, with a variety of load magnitudes. Separate FEA models utilized single point loading, distributed loading, and the construction of a model indenter. Deflections at the loading point demonstrated that all models presented similar findings to those seen in mechanical testing. The similarity of results between the single loading point and the indenter FEA models suggest that either is reasonable for elastic range testing. The significantly shorter CPU run times for the single force models suggest that this may be the best means by which to model orthotropic fiber reinforced dental composites in the elastic range.

scholarly journals Modeling instrumented indentation testing to evaluate the behavior of PA11 and CaCO3 composites for offshore applications

2016 ◽  
Vol 56 ◽  
pp. 140-147 ◽  
Author(s):  
Aline da Costa Rodrigues ◽  
Marco André Abud Kappel ◽  
Christine Rabello Nascimento ◽  
Luciana S. Spinelli ◽  
Ivan Napoleão Bastos ◽  
...  
Keyword(s):  
Indentation Testing ◽  
Instrumented Indentation

Origami-Layer-Jamming Deployable Surgical Retractor With Variable Stiffness and Tactile Sensing

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Hritwick Banerjee ◽  
Tai Kai Li ◽  
Godwin Ponraj ◽  
Senthil Kumar Kirthika ◽  
Chwee Ming Lim ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Surgical Complications ◽  
Variable Stiffness ◽  
Tactile Sensor ◽  
Interaction Force ◽  
Thin Layers ◽  
Medical Applications ◽  
Conductive Ink ◽  
Custom Made ◽  
Near Future

Abstract Origami-based flexible, compliant, and bio-inspired robots are believed to permit a range of medical applications within confined environments. In this article, we experimentally demonstrated an origami-inspired deployable surgical retractor with the controllable stiffness mechanism that can facilitate safer instrument–tissue interaction in comparison to their rigid counterparts. When controllable negative-pressure is applied to the jammed origami retractor module, it becomes more rigid, increasing its strength. To quantify origami-modules strength further, we demonstrated performances of retractor based on the Daler–Rowney Canford paper (38 grams per square meter (gsm)) and sandpaper of 1000 grit. Experiments on the proposed retractor prototype elucidated sandpaper-based retractor can outperform paper-38-gsm retractor for facelift incision with the width of more than 9 cm. Though 38 gsm Canford paper comprised of thin layers, 16 times lesser in thickness than sandpaper, experiments proved its comparable layer jamming (LJ) performance. We leverage the advantage of the LJ mechanism to tune retractor stiffness, allowing the instrument to hold and separate a facelift incision to mitigate the likelihood of surgical complications. The retractor is equipped with a custom-made printed conductive ink-based fabric piezoresistive tactile sensor to assist clinicians with tissue-retractor interaction force information. The proposed sensor showed a linear relationship with the applied force and has a sensitivity of 0.833 N−1. Finally, cadaver experiments exhibit an effective origami-inspired surgical retractor for assisting surgeons and clinicians in the near future.

Manufacture of Accurate Titanium Cranio-Facial Implants with High Forming Angle Using Single Point Incremental Forming

2013 ◽  
Vol 549 ◽  
pp. 223-230 ◽  
Author(s):  
Joost R. Duflou ◽  
Amar Kumar Behera ◽  
Hans Vanhove ◽  
Liciane S. Bertol
Keyword(s):  
Incremental Forming ◽  
Single Point ◽  
Design Feature ◽  
Feature Analysis ◽  
Medical Applications ◽  
Single Point Incremental Forming ◽  
Wall Angle ◽  
Titanium Grade ◽  
Intermediate Part ◽  
Forming Angle

One of the key application areas of Single Point Incremental Forming is in the manufacture of parts for bio-medical applications. This paper discusses the challenges associated with the manufacture of cranio-facial implants with extreme forming angles using medical grade titanium sheets. While on one hand, the failure wall angle is an issue of concern, the parts also need to be manufactured with accuracy at the edges where the implants fit into the human body. Systematic steps taken to overcome these challenges, using intelligent intermediate part design, feature analysis and compensation, are discussed. A number of case studies illustrating the manufacture of accurate parts in aluminium, stainless steel and titanium grade-2 alloy are discussed.

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