Download or read book A Finite Element Model of the Human Head for Simulation of Bone conducted Sound written by You Chang and published by Linköping University Electronic Press. This book was released on 2018-04-03 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bone conduction is usually understood as the hearing sensation based on the vibrations of the skull bone and surrounding tissues. The fact that vibration of the skull bones can result in a sound percept has been known for a long time. However, it is difficult to give a general definition of BC sound. Normally, BC sound is described as the sound energy transmitted through the body (comprising the solid and fluid parts) then the outer, middle and inner ear are involved and finally produce a perception of sound. Even if BC sound perception has been studied for more than a century, the whole pattern of BC sound transmission is still not complete. There are limitations for experimental investigation of BC sound, such as the complexity of experimental manipulations and individual differences between subjects resulting in difficult to interpret outcomes. One way to overcome some of those issues is the use of a simulation model for BC sound. However, until now, the published models are unable to provide a holistic response of BC sound in the human. Therefore, the primary aim of this thesis is to develop a finite element model that could simulate BC sound transmission in the human. Based on cryosectional images of a female, the LiUHead was developed as a FE model of the human head with the structure and material properties of real human. Most the structures and tissues which could contribute to the BC transmission were included in the LiUHead. The simulation results of the LiUHead agreed with experimental data obtained in both cadaver heads and live humans. After the development and validation of the LiUHead, the model was used to investigate BC sound. Since BC sound is transmitted in and between the tissues, the power transmission of BC sound was investigated in the LiUHead in the frequency domain. When the stimulation was applied on the surface of the skull at the mastoid position, the results of the simulations show that, as the name suggest, the skull bone dominants the BC sound transmission. The soft tissues and cartilages are as the second most important media of the BC sound while the skull interior is the least important for the BC transmission. Moreover, according to the power flux in the skull, the BC vibrations are mainly concentrated at the skull base. Other important transmission pathways are located at the occipital bone at the posterior side of the head, but the power transmitted over the face, forehead and vertex is minor. There is power interaction between the skull bone and skull interior near the stimulation position but the transmission of sound power through the brain seem to be minimal. Since the power or energy is difficult to measure in an experimental setting, this investigation gave unique knowledge about BC sound transmission in the head and the interaction between the tissues. As a common application for BC sound, bone-conduction devices are used to stimulate the hearing and is a method for hearing loss rehabilitation. Nowadays many different kinds of BCDs are available. However, most studies failed to compare the different types of BCDs in the same conditions as well as between several BCDs as it is not possible to compare several BCDs within the same subject due to the implantation required for several BCDs. The model gives a unique opportunity to evaluate various BCDs in the same head. Eight different BCDs, including four kinds of skin-drive BCDs, three kinds of direct-drive BCDs, and one in-the-mouth device, were applied to the LiUHead and the simulation results were evaluated. The results proved that the direct-drive BCDs and the in-the-mouth device gave similar vibration responses at the cochlea. At low frequencies, the skin-drive BCDs had similar or even better cochlear responses than the direct-drive BCDs. However, the direct-drive BCDs gave stable responses at mid-frequencies and gave higher responses than the skin-drive BCDs at high frequencies. These results are beneficial evaluating and for designing and improving current BCDs. The ultimate goal of this thesis is to provide a computational model for BC sound that can be used for evaluation of BC sound transmission. This was accomplished by the LiUHead that gave results comparable to experimental data and enabled investigations that cannot easily be conducted in experiments.
Download or read book Modeling Bone Conduction of Sound in the Human Head Using Hp finite Elements written by Paolo Gatto (Ph. D.) and published by . This book was released on 2012 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work focuses on the development of a reliable numerical model for investigating the bone-conduction of sound in the human head. The main challenge of the problem is the lack of fundamental knowledge regarding the transmission of acoustic energy through non-airborne pathways to the cochlea. I employed a fully coupled model based on the acoustic/elastic interaction problem with a detailed resolution of the cochlea region and its interface with the skull and the air pathways. The problem was simulated via hp-finite element approximation, employing a hybrid mesh (tetrahedral, prismatic and pyramidal elements) to better capture the geometrical features of the head. The numerical results thus obtained provide an insight into this fundamental, long standing research problem.
Download or read book A Finite Element Model of a Human Head and a Corresponding Acoustic Test Fixture to Assess the Objective Occlusion Effect Induced by Earplugs Under Bone conducted Stimulation written by Huiyang Xu and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite Element Simulation of External Ear Sound Fields for the Optimization of Eardrum related Measurements written by Sebastian Schmidt and published by Logos Verlag Berlin GmbH. This book was released on 2009-08-31 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sound pressure pT at the human eardrum has essential advantages as reference signal in audiological and psychoacoustical experiments. Unfortunately, precise pressure measurements very close to the tympanic membrane are difficult. In practice, the microphone has to be positioned at a certain distance from the eardrum. The measured pressure then has to be transformed to the eardrum. As a "classical" approach for the estimation of the necessary transfer function, an acoustical network model of the ear canal is developed from geometrical data of the canal (cross-sectional area function) which is in turn determined from measurements of its acoustical input impedance. Such methods, however, do not provide robust results. In this thesis, the concept of one-dimensional models of the ear canal is examined to find the origin of these errors. For this purpose, the sound field at the human external ear was analyzed using finite element models. Inside the canal, irregular three-dimensional structures occur that cannot be modelled accurately using classical one-dimensional network concepts. Upon these findings, an accurate, efficient and highly feasible method for the estimation of pT was developed. Equal-loudness level contours with reference to the eardrum pressure that were measured as pilot application of the new method are presented.
Download or read book A Finite Element Head Injury Model Theory development and results written by T. A. Shugar and published by . This book was released on 1977 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite Element Modeling of the Human Head written by Svein Kleiven and published by . This book was released on 2002 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of the Objective Occlusion Effect Induced Buy Bone condicted Stimulation Using a Three dimensional Finite element Model of a Human Head written by James F. Lynch and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Finite Element Head Injury Model Volume I Theory Development and Results Final Report written by T. A. Shugar and published by . This book was released on 1977 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Finite Element Model of the Human Head written by Yuchen Yan and published by . This book was released on 1988 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Implantable Bone Conduction Hearing Aids written by M. Kompis and published by Karger Medical and Scientific Publishers. This book was released on 2011-03-08 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three decades after the introduction of the first bone-anchored hearing aids, the available systems have improved significantly and the field is expanding faster than ever. New technologies such as digital signal processing have opened new avenues unique to bone conduction hearing aids. Better insights into the physiology of bone-conducted hearing have not only changed the field but also provided ideas for new areas of application.In this volume of Advances in Oto-Rhino-Laryngology, renowned researchers and experienced clinicians from all over the world present the latest findings and practices. Reviews on the theoretical background of bone conduction hearing, presentation of currently available hearing aid systems, chapters on monaural and binaural hearing with implantable bone conduction hearing aids, a comparison with conventional hearing aids and a glimpse into the future of implantable bone conduction hearing aids render this volume an invaluable reference book to ENT surgeons, audiologists, hearing aid acousticians and researchers alike.
Download or read book Modeling the Biodynamical Response of the Human Head for Injury Analysis written by Danielle N. George and published by . This book was released on 2001-09-01 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study is to develop a finite element model of the human head and neck to investigate the biomechanics of head injury. The finite element model is a two-dimensional, plane strain representation of the cervical spine, skull, and major components of the brain including the cerebrum, cerebellum, brain stem, tentorium and the surrounding cerebral spinal fluid. The dynamic response of the model is validated by comparison with the results of human volunteer sled acceleration experiments conducted by Ewing et al. 10 . To validate the head model, one of the head impact experiments performed on cadavers by Nahum et al. 24, is simulated. The model responses are compared with the measured cadaveric test data in terms of head acceleration, and intracranial pressures measured at four locations including the coup and contrecoup sites. The validated model is used to demonstrate that the Head Injury Criterion (HIC), which is based on resultant translational acceleration of the center of gravity of the head, does not relate to the various mechanisms of brain injury and is therefore insufficient in predicting brain injury.
Download or read book Finite Element Modeling of the Human Head Under Impact Conditions written by Maurice Henri André Claessens and published by . This book was released on 1997 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Intelligent Modelling and Simulation written by Aleksander Byrski and published by Springer. This book was released on 2012-04-25 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: The human capacity to abstract complex systems and phenomena into simplified models has played a critical role in the rapid evolution of our modern industrial processes and scienti c research. As a science and an art, Modelling and Simulation have been one of the core enablers of this remarkable human trace, and have become a topic of great importance for researchers and practitioners. This book was created to compile some of the most recent concepts, advances, challenges and ideas associated with Intelligent Modelling and Simulation frameworks, tools and applications. The rst chapter discusses the important aspects of a human interaction and the correct interpretation of results during simulations. The second chapter gets to the heart of the analysis of entrepreneurship by means of agent-based modelling and simulations. The following three chapters bring together the central theme of simulation frameworks, rst describing an agent-based simulation framework, then a simulator for electrical machines, and nally an airborne network emulation environment. The two subsequent chapters discuss power distribution networks from different points of view|anticipation and optimization of multi-echelon inventory policy. After that, the book includes also a group of chapters discussing the mathematical modelling supported by veri cation simulations, and a set of chapters with models synthesised by means of arti cial intelligence tools and complex automata framework. Lastly, the book includes a chapter introducing the use of graph-grammar model for generation of threedimensional computational meshes and a chapter focused on the experimental and computational results regarding simulation of aero engine vortexes. Authors believe, that this book is a valuable reference to researchers and practitioners in the eld, as well as an inspiration to those interested in the area of Intelligent Modelling and Simulation.
Download or read book The Middle Ear written by Sunil Puria and published by Springer. This book was released on 2015-04-20 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The middle ear plays a vital role in the sense and sensitivity of hearing. Of the various characteristics that distinguish mammals from other vertebrates, several pertain specifically to the middle-ear system, such as the presence of three middle-ear bones and the four-layer composite structure of the tympanic membrane. The Middle Ear attempts to elucidate the role this system plays in sound transmission, as viewed from both scientific and clinical perspectives.
Download or read book Finite Element Modeling of Human Middle Ear Based on Histological Sections of One Human Temporal Bone written by Peng Yan and published by . This book was released on 2002 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Finite Element Model of the Human Head for Use in the Study of Pedestrian Accidents written by Timothy James Horgan and published by . This book was released on 2005 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Three dimensional Human Head Finite Element Model and Power Flow in a Human Head Subject to Impact Loading written by Z. Zong and published by . This book was released on 2006 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A three-dimensional finite element model of the human head is presented. The model has been validated against two sets of experimental results. To assess injury likelihood of the head subjected to impact loading, the structural intensity (SI) methodology is introduced in accordance with the prevailing practice in experimental biomechanics. SI is a vector quantity indicating the direction and magnitude of power flow inside a dynamically loaded structure. In this paper, the SI field inside the head model is computed for three cases, namely frontal, rear and side impacts. The results for the three cases have revealed that there exist power flow paths. The skull is, in general, a good energy flow channel. The study has also revealed the high possibility of spinal cord injury due to wave motion inside the head.
