821 research outputs found
Development of a SolidWorks Simulation Toolkit for a Sophomore Level Biomedical Engineering Course
In the engineering industry, computer-aided design (CAD) programs are used to create models and create virtual experiments or studies that allow engineers to observe the real behavior of parts or assemblies under certain conditions. Companies hire students with experience in CAD, as professionals believe that CAD experience is beneficial [1,2]. SolidWorks is among the most popular CAD software used by engineers. SolidWorks has multiple functionalities that also allow for finite element analysis dependent on the license. Users can create simulation studies in SolidWorks Simulation that can be used as an accurate approximation for real results.
The goal of this study is to create a toolkit for students in Biomechanical Engineering that will allow students to access a variety of models and simulations based on homework problems and lecture examples they have seen in class. The purpose of this study is to help students understand core topics being taught within the class as well as introduce students to advanced uses of CAD software such as SolidWorks Simulation. Data is collected from the students via a survey, asking about their experience, interest, and proficiency with using SolidWorks. Students were also asked to give free response feedback as well, allowing them to highlight the problems they had so that they can be fixed in future updates.
The results of this study show that students overall respond positively to the module’s implementation. While the students found that it was difficult to use the toolkit and the software, on average students have agreed that SolidWorks Simulation is a useful tool. Students were also only moderately confident in using the software. Going forward, all the student’s feedback will be considered to make further progress into the development of the toolkit
ME-EM 2017-18 Annual Report
Table of Contents Curriculum Revision The Result: MEP I-IV ME-EM Research Alumni Features Enrollment & Degrees Graduates Faculty & Staff Alumni Donors Contracts & Grants Patents & Publicationshttps://digitalcommons.mtu.edu/mechanical-annualreports/1001/thumbnail.jp
A biomechanical approach for real-time tracking of lung tumors during External Beam Radiation Therapy (EBRT)
Lung cancer is the most common cause of cancer related death in both men and women. Radiation therapy is widely used for lung cancer treatment. However, this method can be challenging due to respiratory motion. Motion modeling is a popular method for respiratory motion compensation, while biomechanics-based motion models are believed to be more robust and accurate as they are based on the physics of motion. In this study, we aim to develop a biomechanics-based lung tumor tracking algorithm which can be used during External Beam Radiation Therapy (EBRT). An accelerated lung biomechanical model can be used during EBRT only if its boundary conditions (BCs) are defined in a way that they can be updated in real-time. As such, we have developed a lung finite element (FE) model in conjunction with a Neural Networks (NNs) based method for predicting the BCs of the lung model from chest surface motion data.
To develop the lung FE model for tumor motion prediction, thoracic 4D CT images of lung cancer patients were processed to capture the lung and diaphragm geometry, trans-pulmonary pressure, and diaphragm motion. Next, the chest surface motion was obtained through tracking the motion of the ribcage in 4D CT images. This was performed to simulate surface motion data that can be acquired using optical tracking systems. Finally, two feedforward NNs were developed, one for estimating the trans-pulmonary pressure and another for estimating the diaphragm motion from chest surface motion data.
The algorithm development consists of four steps of: 1) Automatic segmentation of the lungs and diaphragm, 2) diaphragm motion modelling using Principal Component Analysis (PCA), 3) Developing the lung FE model, and 4) Using two NNs to estimate the trans-pulmonary pressure values and diaphragm motion from chest surface motion data. The results indicate that the Dice similarity coefficient between actual and simulated tumor volumes ranges from 0.76±0.04 to 0.91±0.01, which is favorable. As such, real-time lung tumor tracking during EBRT using the proposed algorithm is feasible. Hence, further clinical studies involving lung cancer patients to assess the algorithm performance are justified
Biomechanics and Remodelling for Design and Optimisation in Oral Prosthesis and Therapeutical Procedure
The purpose of dental prostheses is to restore the oral function for edentulous patients. Introducing any dental prosthesis into mouth will alter biomechanical status of the oral environment, consequently inducing bone remodelling. Despite the advantageous benefits brought by dental prostheses, the attendant clinical complications and challenges, such as pain, discomfort, tooth root resorption, and residual ridge reduction, remain to be addressed. This thesis aims to explore several different dental prostheses by understanding the biomechanics associated with the potential tissue responses and adaptation, and thereby applying the new knowledge gained from these studies to dental prosthetic design and optimisation. Within its biomechanics focus, this thesis is presented in three major clinical areas, namely prosthodontics, orthodontics and dental implantology. In prosthodontics, the oral mucosa plays a critical role in distributing occlusal forces a denture to the underlying bony structure, and its response is found in a complex, dynamic and nonlinear manner. It is discovered that interstitial fluid pressure in mocosa is the most important indicator to the potential resorption induced by prosthetic denture insertion, and based on this finding, patient-specific analysis is performed to investigate the effects caused by various types of dentures and prediction of the bone remodelling activities. In orthodontic treatments, a dynamic algorithm is developed to analyse and predict potential bone remodelling around the target tooth during orthodontic treatment, thereby providing a numerical approach for treatment planning. In dental implantology, a graded surface morphology of an implant is designed to improve osseointegration over that of a smooth uniform surface in both the short and long term. The graded surface can be optimised to achieve the best possible balance between the bone-implant contact and the peak Tresca stress for the specific clinical application need
Radiolucent Loading Device for Computed Tomography Imaging
There is a limited availability of portable compressional loading devices, none of which work within a computed tomography (CT) scanner. This is due to the lack of radiolucent materials these devices are made of, which make artifacts that disrupt the final CT image. Combining both testing and imaging can advance understanding of how materials behave at a microstructural level. This paper describes the design and fabrication of a novel device that can be used within a CT scanner to collect images of compressed bone samples. Validation testing showed that specimens could be compressed up to 2000 Newtons of force over 26 millimeters of displacement within 8 Newtons and 0.071 millimeters of accuracy
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Micromechanics of Human Bone: Role of Architecture and Tissue Material Properties
Knowledge of the biomechanical behavior and failure mechanisms of human bone is fundamental to understanding the etiology of bone fractures as well as the mechanisms by which aging, disease, and treatment can alter the mechanical competence of bone. In this context, the focus of this dissertation was to enhance the current understanding of the biomechanical mechanisms of bone strength, and more specifically, to elucidate the role of architecture and tissue material properties in overall bone strength and whole-bone failure behavior.Using the latest advances in micro-computed tomography and high-resolution finite element modeling, we investigated the effect of typical population-variations in tissue-level ductility on human vertebral strength. We found that compared to the reference case, varying both cortical and trabecular tissue ultimate strains by ±1 SD from their mean values changed vertebral strength by at most ±8%, an effect that was relatively uniform across all the specimens. Overall strength changed similarly for similar (±1 SD) changes in trabecular versus cortical ductility. Further analysis revealed that only a tiny proportion of tissue failed (< 2%) when the whole bone reached its point of structure-level failure, and that the failure mode and location of this tiny amount were relatively insensitive to typical variations in tissue ductility. These findings suggest that it is the overall load transfer within the whole vertebral body —determined by bone volume fraction and microstructure— that dictates where failure occurs rather than typical variations in the ductility of the tissue. Together these findings suggest that typical variations in tissue ductility might have a relatively modest impact on vertebral strength compared to the multiple-fold variations in vertebral strength that are typically observed across any elderly population.Combining micro-computed tomography, high-resolution finite element modeling and biomechanical testing, we sought to provide further insight into the tissue modulus of trabecular bone and better elucidate its relation with bone volume fraction and trabecular microarchitecture. Our results indicated that effective tissue modulus of vertebral trabecular bone varied greatly among the specimens and was negatively correlated with bone volume fraction of each vertebra (R2 = 0.51, p < 0.05). These results suggest that there can be 3X variation in tissue modulus across the elderly human vertebrae, about 50% of which may be explained by variations in bone volume fraction. Together these findings suggest that as trabecular bone becomes older and thus more porous due to an imbalance between bone formation and resorption, the tissue may become stiffer to compensate for the bone loss.The work presented in this dissertation has also provided substantial insight into the structure–function relations for trabecular bone from different anatomic sites. We investigated the main structure–function relation —characterized by bone volume fraction versus on-axis yield stress— for human calcaneal trabecular bone and compared this relation to that for trabecular bone from other anatomic sites. We found that the relation between yield stress and bone volume fraction of the calcaneus was most similar to that of the proximal tibia. Furthermore, our results demonstrated that while there was no universal yield stress–bone volume fraction relation for trabecular bone across different anatomic sites for on-axis loading, the general (normalized) yield stress–bone volume fraction relation was similar for all sites. This similarity in the normalized relation suggests that a given percentage deviation from the mean bone mass has the same mechanical consequence at the calcaneus as it does at the other anatomic sites.In closure, this dissertation provides answers to some of the fundamental questions regarding the role of architecture and tissue material properties in explaining the variations in overall bone strength across individuals, and provides new insight into the etiology of age-related fractures. This work also outlines potential areas of future research to further advance our current understanding of overall bone strength and fracture etiology
Three-dimensional modeling of the human jaw/teeth using optics and statistics.
Object modeling is a fundamental problem in engineering, involving talents from computer-aided design, computational geometry, computer vision and advanced manufacturing. The process of object modeling takes three stages: sensing, representation, and analysis. Various sensors may be used to capture information about objects; optical cameras and laser scanners are common with rigid objects, while X-ray, CT and MRI are common with biological organs. These sensors may provide a direct or an indirect inference about the object, requiring a geometric representation in the computer that is suitable for subsequent usage. Geometric representations that are compact, i.e., capture the main features of the objects with a minimal number of data points or vertices, fall into the domain of computational geometry. Once a compact object representation is in the computer, various analysis steps can be conducted, including recognition, coding, transmission, etc. The subject matter of this dissertation is object reconstruction from a sequence of optical images using shape from shading (SFS) and SFS with shape priors. The application domain is dentistry. Most of the SFS approaches focus on the computational part of the SFS problem, i.e. the numerical solution. As a result, the imaging model in most conventional SFS algorithms has been simplified under three simple, but restrictive assumptions: (1) the camera performs an orthographic projection of the scene, (2) the surface has a Lambertian reflectance and (3) the light source is a single point source at infinity. Unfortunately, such assumptions are no longer held in the case of reconstruction of real objects as intra-oral imaging environment for human teeth. In this work, we introduce a more realistic formulation of the SFS problem by considering the image formation components: the camera, the light source, and the surface reflectance. This dissertation proposes a non-Lambertian SFS algorithm under perspective projection which benefits from camera calibration parameters. The attenuation of illumination is taken account due to near-field imaging. The surface reflectance is modeled using the Oren-Nayar-Wolff model which accounts for the retro-reflection case. In this context, a new variational formulation is proposed that relates an evolving surface model with image information, taking into consideration that the image is taken by a perspective camera with known parameters. A new energy functional is formulated to incorporate brightness, smoothness and integrability constraints. In addition, to further improve the accuracy and practicality of the results, 3D shape priors are incorporated in the proposed SFS formulation. This strategy is motivated by the fact that humans rely on strong prior information about the 3D world around us in order to perceive 3D shape information. Such information is statistically extracted from training 3D models of the human teeth. The proposed SFS algorithms have been used in two different frameworks in this dissertation: a) holistic, which stitches a sequence of images in order to cover the entire jaw, and then apply the SFS, and b) piece-wise, which focuses on a specific tooth or a segment of the human jaw, and applies SFS using physical teeth illumination characteristics. To augment the visible portion, and in order to have the entire jaw reconstructed without the use of CT or MRI or even X-rays, prior information were added which gathered from a database of human jaws. This database has been constructed from an adult population with variations in teeth size, degradation and alignments. The database contains both shape and albedo information for the population. Using this database, a novel statistical shape from shading (SSFS) approach has been created. Extending the work on human teeth analysis, Finite Element Analysis (FEA) is adapted for analyzing and calculating stresses and strains of dental structures. Previous Finite Element (FE) studies used approximate 2D models. In this dissertation, an accurate three-dimensional CAD model is proposed. 3D stress and displacements of different teeth type are successfully carried out. A newly developed open-source finite element solver, Finite Elements for Biomechanics (FEBio), has been used. The limitations of the experimental and analytical approaches used for stress and displacement analysis are overcome by using FEA tool benefits such as dealing with complex geometry and complex loading conditions
Podiatrists’ and orthotists’ views and experiences of using plantar pressure measurement in the assessment and treatment of diabetic foot syndrome
Background: The measurement of plantar pressure is recommended as a clinical tool for risk assessment, prevention and treatment of diabetic foot ulceration. To first assess comprehensively the available evidence on the use of plantar pressure assessment (PPA) to guide footwear and insole design and modification in people with diabetic foot disease, a systematic review was undertaken. Although the current evidence supports the use of PPA in diabetic foot management, the implementation of the technology in a clinical setting faces barriers such as competency, cost, time, etc. Therefore, a qualitative study was conducted to determine the barriers and facilitators of clinical usage of PPA according to podiatrists’ and orthotists’ views and experiences in the assessment and treatment of diabetic foot syndrome.Method: The literature search for the systematic review utilised Medline/Pubmed, Scopus, Cochrane, Clinical Trials, and CINAHL databases. In terms of qualitative study, 4 Podiatrists and 2 Orthotists with and without experience of using plantar pressure measurement were recruited. Six semi-structured online interviews were conducted; the audio was recorded and transcribed. Then, inductive thematic analysis was used to analyse transcribed texts. Result: The systematic review provides support for the use of PPA to optimise footwear and insole for the prevention of ulcer recurrence, and plantar pressure reduction in the diabetic foot. The qualitative study revealed some barriers and facilitators to improve the clinical implementation of PPA. As a result, six themes have been defined: 1. The importance of training and education in clinical implementation of PPA, 2. Providing evidence for the NHS to prove the benefits of PPA, 3. Time and space, 4. Human resources 5. Specific triage 6. Cost. Clinicians were overwhelmingly in support of plantar pressure measurement to demonstrate high areas of pressure in people with diabetes. However, lack of knowledge, time and space were considered as the main barriers in clinical implementation of PPA. Conclusion: The advantages of the use of plantar pressure data for insole and footwear modifications in people with diabetes have been supported by the evidence. However, the barriers to implementation of PPA include lack of knowledge and education about the use and interpret of plantar pressure data, shortage of time and space in routine clinical practice, and high cost of purchase and implementation of this technology.Training in using plantar pressure device and interpreting the data is a key factor. Besides, providing evidence for the NHS is an important thing to bring the effectiveness of PPA into consideration. The NHS can allocate specific clinics and time to facilitate the clinical use of PPA
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