María Ángeles Martínez-Calvo

Using the Finite Element Method to Determine the Influence of Age, Height and Weight on the Vertebrae and Ligaments of the Human Spine

This study uses the Finite Element Method (FEM) to analyze the influence of age, height and weight on the vertebrae and ligaments of the human functional spinal unit (FSU). Two different artificial segments and the influence of the patient’s age, sex and height were considered. The FSU analyzed herein was based on standard human dimensions. It was fully parameterized first in engineering modelling format using CATIA© software. A combination of different elements (FE) were developed with Abaqus© software to model a healthy human FSU and the two different sizes of artificial segments. Healthy and artificial FSU Finite Element models (FE models) were subjected to compressive loads of differing values. Spinal compression forces, posture data and male/female anthropometry were obtained using 3DSSPP© software Heights ranging from 1.70 to 1.90 meters; ages, between 30 and 80 years and body weights between 75 and 90 kg were considered for both men and women. Artificial models were based on the Charite prosthesis. The artificial prosthesis consisted of two titanium alloy endplates and an ultra-high-molecular-weight polyethylene (UHMWPE) core. An analysis in which the contacts between the vertebrae and the intervertebral disc, as well as the behavior of the seven ligaments, were taken into consideration. The Von Mises stresses for both the cortical and trabecular bone of the upper and lower vertebrae, and the longitudinal stresses corresponding to the seven ligaments that connect the FSU were analyzed. The stresses obtained for the two geometries that were studied by means of the artificial FE models were very similar to the stresses that were obtained from healthy FE models.

The design of a knee prosthesis by Finite Element Analysis

The purpose of this paper is to study two types of knee prosthesis that are based on the Finite Element Method (FEM). The process to generate the Finite Element (FE) models was conducted in several steps. A 3D geometric model of a healthy knee joint was created using 3D scanned data from an anatomical knee model. This healthy model comprises a portion of the long bones (femur, tibia and fibula) as well as by the lateral and medial meniscus, cartilage and ligaments. The digital model that was obtained was repaired and converted to an engineering drawing format using CATIA© software. Based on the foregoing format, two types of artificial knee prostheses were designed and assembled. Mentat Marc© software was used to model the healthy and artificial knee FE models. The healthy and artificial knee FE models were subjected to different loads. The an-thropometry of the human body that was studied and the combination of loads to apply to the knee were obtained by use of 3D Static Strength Prediction software (3DSSPP©). The Von Mises stresses, as well as all the relative displacements of the components of the healthy and artificial knee FE model, were obtained from the Mentat Marc© software. The Von Mises stresses for both the cortical and the trabecular bone of the artificial and healthy knee FE model were analyzed and compared. The stresses that were obtained from the two knee prosthesis that were studied based on the artificial FE models were very similar to those stresses that were obtained from healthy FE models.

Characterization of a Composite Material Reinforced with Vulcanized Rubber

The paper is intended to propose a method to characterize the adhesion of a thermoplastic matrix composite material that is reinforced with continuous fibers and over-injected vulcanized rubber. The behaviour of the material based on the thermoplastic matrix and the adhesive is studied. In addition, the combination of factors that provides the greatest possible adhesion of the rubber to the composite is analyzed. Test methods are also analysed and suggested to characterize the adhesion force of the vulcanized rubber to the thermoplastic composite.

Reliable low-cost alternative for modeling and rendering 3D Objects in Engineering Graphics Education

In Engineering Schools is a growing concern to offer its students the latest in 3D CAD modeling software that respond to advanced design needs. The latest software is increasingly comprehensive and complex. However, the time available for teaching such software is scarce and rarely get to know more than 20% of the potential of the software for a particular area. However, other 3D CAD solutions are on the market, low cost, very friendly, easy to learn interface, with much potential and you will get to have all the features of more advanced software, can fully meet the teaching requirements this area. Since the introduction of the EHEA (European Higher Education Area), the target level of teaching an engineering school in the field of 3D CAD modeling, should be to develop in students in the time available, the maximum capacities and skills three-dimensional geometric design. And this, when well planned, can be achieved with the proper use of low cost software. The authors have analyzed the potential of various freeware or shareware software, well suited to the typical subjects of Engineering Design, in the areas of CAD-3D design and rendering.