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Effect of different feed-rate in bone drilling: experimental and numerical study

Publication . Fernandes, M.G.A.; Fonseca, E.M.M.; Natal, Renato

The behaviour of bone tissue during drilling has been subject of recent studies due to its great importance. Because of thermal nature of the bone drilling, high temperatures and thermal mechanical stresses are developed during drilling that affect the process quality. However, there is still a lack information with regard to the distribution of mechanical and thermal stresses during bone drilling. The present paper describes a sequentially coupled thermal-stress analysis to assess the mechanical and thermal stress distribution during bone drilling. A three-dimensional thermo-mechanical model was developed using the ANSYS/LSDYNA finite element code under different drilling conditions. The model incorporates the dynamic characteristics of drilling process, as well as the thermo-mechanical properties of the involved materials. Experimental tests with polyurethane foam materials were also carried out. It was concluded that the use of higher feed-rates lead to a decrease of normal stresses and strains in the foam materials. The experimental and numerical results were compared and showed good agreement. The proposed numerical model could be used to predict the better drilling parameters and minimize the bone injuries.

2016Conference object

Open access

Effect of drill speed during drilling of human cadaveric tibiae

Publication . Fernandes, M.G.A.; Fonseca, E.M.M.; Natal, Renato; Manzanares, Cristina; Azevedo, Lucas D.

Bone fracture is a feature of everyday life. Most of the treatments involve bone drilling to fixation of implanted medical devices. Bone loss due to excessive produced heat during drilling may weaken the purchase of surgically placed screws and pins, causing them to loosen postoperatively. Decrease the heat generation has a great demand as it helps in better fixation and healing of bone tissue. This paper presents an experimental model to study the effect of drill speed using human cadaveric tibiae. The results revealed that the temperature rise and the duration of temperature elevation decreased when lower drill speeds are used.

2017Conference object

Open access

Temperature assessment in the drilling of composite materials and ex-vivo porcine bones

Publication . Fernandes, Maria Goreti Antunes; Fonseca, E.M.M.; Natal, Renato; Dias, Maria Isabel Ribeiro

This study presents different experimental methodologies for analysis and temperature evaluation during the drilling process of composite materials and ex-vivo porcine bones. In the experimental methodologies were evaluated the influence of different parameters on the bone temperature rise. The combinations of different parameters produced temperatures far below the critical values. It was concluded that drill temperature decreases when the feed-rate is higher and, independently, increases with the increasing of hole depth. The influence of drill speed is not clear. In the composite materials the temperature decreases in the drill bit when the drill speed is higher, and in ex-vivo porcine bones happens the opposite. The animal models recorded lower temperature values than composite materials.

2015Conference object

Open access

Thermal analysis in drilling of ex vivo bovine bones

Publication . Fernandes, M.G.A.; Fonseca, E.M.M.; Jorge, Renato N.; Vaz, Madalena; Dias, Maria Isabel Ribeiro

Bone drilling is a common procedure in Medicine, mainly in traumatology and orthopedic procedure for fractures fixation and in reconstructive surgery. The success of this surgical procedure is dependent on many factors, namely, on heat generation control during the bone drilling. The main concern in bone drilling is the mechanical and thermal damage of the bone induced by inappropriate parameters such as drill speed and feed-rate during the drilling. This study focuses on the temperature generated during drilling of cortical bone tissue (bovine origin) and solid rigid polyurethane foams with similar mechanical properties to the human bone tissue. Different parameters such as drill speed, feed-rate and hole depth were tested. All results showed that improvement of the drilling parameters and the drill temperatures can be estimated. It was concluded that when the drill speed and feed-rate were higher, the bone temperature increase was lower. The obtained results of temperature in the drilling process of polyurethane foam blocks or bovine bone were compared with a good agreement in between both. © 2017 World Scientific Publishing Company.

2017Journal article

Open access

Three-dimensional dynamic finite element and experimental models for drilling processes

Publication . Fernandes, M.G.A.; Fonseca, E.M.M.; Natal, Renato

The main goal of this paper is to assess the mechanical damage in solid rigid foam materials with similar mechanical properties to the human bone induced by the cutting parameters. In the present study, a three-dimensional dynamic finite element model was developed to simulate the drilling process in solid rigid foam materials and it was validated with experimental results. Using an explicit dynamic numerical simulation, it is possible to obtain large structural deformation with high load intensity in short time frame. The developed model is used to study the effects of different high intensity loads distribution in the solid rigid foam materials. Laboratory tests were produced using biomechanical test blocks instrumented with strain gauges in different surface positions during the drilling process. The comparison between the numerical and the experimental results enables the evaluation and improvements of the cutting process. It was concluded when the feed-rate is higher, the stresses and strains in the solid rigid foam material are lower. The developed numerical model proved to be a great tool in this kind of analysis and available to use in forthcoming tests.

2018Journal article

Restricted access