This thesis details a study of the structural behavior of Hybrid-Composite Beams (HCB) consisting of a fiber reinforced polymer (FRP) shell with a concrete arch tied with steel prestressing strands.  The HCB offers advantages in life cycle costs through reduced transportation weight and increased corrosion resistance. By better understanding the system behavior, the proportion of load in each component can be determined, and each component can be designed for the appropriate forces. A long term outcome of this research will be a general structural analysis framework that can be used by DOTs to design HCBs as rapidly constructible bridge components. This study focuses on identifying the load paths and load sharing between the arch and FRP shell. Testing was performed by applying point loads on simple span beams (before placing the bridge deck) and a three beam skewed composite bridge system.  Curvature from strain data is used to find internal bending forces, and the proportion of load within the arch is found. Additionally, a stress integration method is used to confirm the internal force contributions.  The tied arch carries about 80% of the total load for the non-composite case without a bridge deck.  When composite with a bridge deck, the arch has a minimal contribution to the HCB stiffness and strength as it is below the neutral axis. For this composite case the FRP shell and prestressing strands resist about 85% of the applied load while the bridge deck carries the remaining 15% to the end diaphragms and bearings. / Master of Science

Shear walls are the primary lateral load resisting elements in bearing wall systems used in masonry construction. Horizontal loads due to wind or earthquake are transferred to vertical walls by diaphragms that are rigid such as concrete floor slabs or flexible such as wood floors. With rigid diaphragms, loads are apportioned to the supporting walls based on their relative rigidity. Walls with openings accommodating doors and windows (“perforated walls”) have reduced rigidity that can be determined using available hand calculation methods. These methods primarily focus on analysis procedures, not on the visualization of the load path that is critically important in structural engineering practice. The analogy of springs in series or parallel is used to determine the equivalent stiffness of elastic systems in structural dynamics. This thesis uses this analogy to develop a method that can help visualize load flow in perforated shear walls connected to rigid diaphragms. Rigidities are calculated using existing methods and combined as springs in series or parallel to represent a perforated wall. Loads taken by the wall segments correspond to the electrical current flowing through this imaginary “circuit”. To help visualize the load path, the line drawing representation of springs in series or parallel and the applied lateral load are deliberately oriented in the vertical direction. The application of the analogy is illustrated by several numerical examples of varying complexity taken from text books. Finite element solutions are included in the comparisons to provide a measure of the relative accuracy of hand calculation methods. The analogy can be extended to refine existing hand calculation methods though this increases computational effort. It improves accuracy but only for cases where the aspect ratio of the wall segments is such that shear effects are dominant.

The internal dynamics of powder systems under compression are as of yet not fully understood, and thus there is a necessity for approaches that can help in further clarifying and enhancing the level of understanding on this subject. To this end, the internal dynamics of powder systems under compression were probed by means of force distributions and a novel compaction equation. The determination of force distributions hinged on the use of carbon paper as a force sensor, where the imprints transferred from it onto white paper where converted through calibration into forces. Through analysis of these imprints, it was found that the absence of friction and bonding capacity between the particles composing the powder bed had no effect on how the applied load was transferred through the system. Additionally, it was found that pellet strength had a role to play in the homogeneity of force distributions, where, upon the occurrence of fracture, force distributions became less homogenous. A novel compaction equation was derived and tested on a series of systems composed of pellets with differing mechanical properties. The main value of the equation lay in its ability to predict compression behavior from single particle properties, and the agreement was especially good when a compact of zero porosity was formed. The utility of the equation was tested in two further studies, using a series of pharmaceutically relevant powder materials. It was established that the A parameter of the equation was a measure of the deformability of the powder material, much like the Heckel 1/K parameter, and can be used as a means to rank powders according to deformability, i.e. to establish plasticity scale. The equation also provided insights into the dominating compression mechanisms through an invariance that could be exploited to determine the point, at which the powder system became constrained, i.e. the end of rearrangement. Additionally, the robustness of the equation was demonstrated through fruitful analysis of a set of diverse materials. In summary, this thesis has provided insights and tools that can be translated into more efficient development and manufacturing of medicines in the form of tablets.

This thesis is part of a major research project to analyse vibro-acoustic characteristics from variable speed inverter driven induction motors (VSIDIM). The overall projects??? aimed at providing a better understanding of the mechanisms of sound generation from electromagnetic origins and developing a numerical model to predict the sound power emitted from a VSIDIM. The scope of this thesis is to assess experimentally the effect of various controller strategies on the radiated sound power and to develop a finite element method for calculating the electromagnetic force distribution over the stator. Various sources of noise in induction motors and their behaviour with speed and load have been reviewed. Models of the electromagnetic field and vibro-acoustic character have been discussed. An outline of various techniques of reducing noise in induction motors through design of inverters and modifications to the motor structure has been given. Experiments were conducted to assess the effect of controller strategies on the radiated sound power. Three different supplies were tested: a dynamotor which produces an almost sinusoidal supply with very low harmonic content, an inverter with a low switching frequency (less than 1kHz) and an inverter with a high switching frequency (8kHz) and various levels of random modulation. Results indicate that the sound power level of the MSC drive is a lot higher than that of the VSC 2000 drive and the dynamotor drive. The sound power level of the VSC 2000 drive and the dynamotor drive increases almost linearly with motor speed, that for the MSC drive is almost independent of speed. The sound power level of the MSC drive is almost 28dB higher than that of the dynamotor drive at 450rpm and the difference is reduced to 14dB at 1500rpm where the aerodynamic noise becomes more dominant. It has been found that at the rated speed (1500rpm), the sound power level varies by less than 3dB from no load to full load for all three sources. Although increasing the switching frequency increases the cost of the inverters and switching losses, results from the MSC and VSC 2000 drives clearly show that it reduces the radiated sound power by shifting the harmonics into higher and inaudible frequency range. The tonal nature around the switching frequency has been reduced by increasing the levels of random modulation to spread the energy over a wider range of frequencies, although the sound power level has not varied by more than 0.2dB. A finite element model has been developed to calculate the electromagnetic force distribution. The quasi-static solution method has been implemented by stepping the rotor through the time domain using a fine regular mesh in the air gap. The stator currents were experimentally obtained while the rotor currents were obtained using a 4 parameter state space model of the motor. Results of the simulation indicate the influence of stator and rotor slots, saturation and time harmonics in the current. The calculated electromagnetic force distribution has been used in a FEM/BEM acoustic model and SEA acoustic model to predict the radiated sound power which agrees reasonably well with the measured sound, thus validating indirectly the electromagnetic force simulations.

This thesis is part of a major research project to analyse vibro-acoustic characteristics from variable speed inverter driven induction motors (VSIDIM). The overall projects??? aimed at providing a better understanding of the mechanisms of sound generation from electromagnetic origins and developing a numerical model to predict the sound power emitted from a VSIDIM. The scope of this thesis is to assess experimentally the effect of various controller strategies on the radiated sound power and to develop a finite element method for calculating the electromagnetic force distribution over the stator. Various sources of noise in induction motors and their behaviour with speed and load have been reviewed. Models of the electromagnetic field and vibro-acoustic character have been discussed. An outline of various techniques of reducing noise in induction motors through design of inverters and modifications to the motor structure has been given. Experiments were conducted to assess the effect of controller strategies on the radiated sound power. Three different supplies were tested: a dynamotor which produces an almost sinusoidal supply with very low harmonic content, an inverter with a low switching frequency (less than 1kHz) and an inverter with a high switching frequency (8kHz) and various levels of random modulation. Results indicate that the sound power level of the MSC drive is a lot higher than that of the VSC 2000 drive and the dynamotor drive. The sound power level of the VSC 2000 drive and the dynamotor drive increases almost linearly with motor speed, that for the MSC drive is almost independent of speed. The sound power level of the MSC drive is almost 28dB higher than that of the dynamotor drive at 450rpm and the difference is reduced to 14dB at 1500rpm where the aerodynamic noise becomes more dominant. It has been found that at the rated speed (1500rpm), the sound power level varies by less than 3dB from no load to full load for all three sources. Although increasing the switching frequency increases the cost of the inverters and switching losses, results from the MSC and VSC 2000 drives clearly show that it reduces the radiated sound power by shifting the harmonics into higher and inaudible frequency range. The tonal nature around the switching frequency has been reduced by increasing the levels of random modulation to spread the energy over a wider range of frequencies, although the sound power level has not varied by more than 0.2dB. A finite element model has been developed to calculate the electromagnetic force distribution. The quasi-static solution method has been implemented by stepping the rotor through the time domain using a fine regular mesh in the air gap. The stator currents were experimentally obtained while the rotor currents were obtained using a 4 parameter state space model of the motor. Results of the simulation indicate the influence of stator and rotor slots, saturation and time harmonics in the current. The calculated electromagnetic force distribution has been used in a FEM/BEM acoustic model and SEA acoustic model to predict the radiated sound power which agrees reasonably well with the measured sound, thus validating indirectly the electromagnetic force simulations.

Background: Hallux valgus (HV) is one of the most common foot deformities. Considering the fact that 23% of adults develop such condition during their lifetime, understanding HV is badly needed. Plantar pressure technologies are used widely for determination of biomechanical changes in foot during walking. There are already published claims relating to the pressure distribution of HV condition. Association of HV to sole pressure widely presented as a means of identifying such condition. Methods: plantar pressure patterns can be linked to the deformity progression or existence, extracting some patterns out of force measurements can be beneficial in recognizing the patients with and without deformity. The dynamic changes of the forces that applied to the fore-foot in volunteers with and without HV when they walked at self-selected and fast speeds were examined. Furthermore, Markovian chain transfer matrices were used to obtain the transfer coefficient of the force among five metatarsals. Another method was to measure the lateral flexibility of the 1st metatarsal joint as an indication of HV deformity by Motion Capture cameras. Finally, two 3D feet models of HV and non-HV volunteers were made in Mimics software and then in FEA (finite element analysis) the stress distribution under the foot was validated with the experiments. Results: The higher forces were observed under the 2nd, 3rd and 1st metatarsal heads in both speeds but the results obtained were significantly different among groups and in fast speed and under 3rd and 1st metatarsals in self-selected speed. In this study the use of Markovian transfer matrices as a means of characterising the gait pattern is new and novel. It was intended that highest coefficients of the matrix would indicate the existence of HV, however studies showed that the biggest difference between HV and non HV patients was the scatter of the coefficients which shown to give very strong indication of the existence of HV. It was shown by kinematic studies and also it was found that the 1st metatarsal joint was significantly more flexible in HV patients compared to non–HV individuals. Finally FEA studies has shown that in the 3D feet models of both volunteers (with and without HV), the highest stress was under the heal area and then transfers towards fore-foot area. In patient with HV the higher force were seen under the 1st to 3rd metatarsal heads compare to non-HV individual and each model was validated its related experiments. Conclusion: it was observed that there was a significant variability of pressure distribution of the same individual from one trial to another indicating that getting consistent pressure pattern is an important hurdle to overcome in our studies, raised loading is observed on Metatarsal 2, 3 and 1 in HV patients and it was possible to give statistical significance to these findings. In this thesis, it was intended to obtain early diagnostics of HV condition and much work was put in this, however outcome was not conclusive. However it was possible to distinguish HV form non-HV volunteers from the scatter characteristics of the transfer pattern. Investigation of the 1st metatarsal joint laxity of non-HV and HV patients revealed that HV individuals were significantly higher compared to non–HV volunteers and this can be used as an indication of HV existence. Finally, the 3D models show that FEA is a reliable tool as the FEA study showed good correlation with the experimental results.

No description available.

No description available.

All living organisms utilize thousands of molecular building blocks to perform mechanical tasks. These building blocks are mostly proteins, and their mechanical properties define the way they can be utilized by the cell. The spectrum ranges from rope like structures that give hold and stability to our bodies to microscopic engines helping us to perform or sense mechanical work. An increasing number of biological processes are revealed to be driven by force and well-directed distribution of strain is the very base of many of these mechanisms. We need to be able to observe the distribution of strain within bio-molecules if we want to gain detailed insight into the function of these highly complex nano-machines. Only by theoretical understanding and prediction of mechanical processes on the molecular level will we be able to rationally tailor proteins to mimic specific biological functions. This thesis aims at understanding the molecular mechanics of a wide range of biological molecules, such as the muscle protein titin or silk fibers. We introduce Force Distribution Analysis (FDA), a new approach to directly study the forces driving molecular processes, instead of indirectly observing them by means of coordinate changes.

Submitted by FABIAN RODRIGO CASTRO FORERO null (fabiancastroforero@yahoo.com) on 2016-05-25T17:32:02Z No. of bitstreams: 1 castro_fr_me_ilha.pdf: 5058433 bytes, checksum: bf5b2af2ddbd3137fd6e825d60119c97 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-05-31T13:28:40Z (GMT) No. of bitstreams: 1 castro_fr_me_ilha.pdf: 5058433 bytes, checksum: bf5b2af2ddbd3137fd6e825d60119c97 (MD5) / Made available in DSpace on 2016-05-31T13:28:40Z (GMT). No. of bitstreams: 1 castro_fr_me_ilha.pdf: 5058433 bytes, checksum: bf5b2af2ddbd3137fd6e825d60119c97 (MD5) Previous issue date: 2016-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O pé é o órgão base da sustentação do corpo humano que está constantemente submetido a esforços para garantir a estabilidade deste. Analisando-se a distribuição de força na região plantar de indivíduos, pode-se inferir a respeito de patologias nos pés, problemas posturais e de equilíbrio. O estudo da distribuição de força na região plantar é feito com o baropodômetro, um equipamento composto por sistemas de hardware e software. Neste trabalho é apresentado o desenvolvimento de um baropodômetro implementado no Laboratório de Instrumentação e Engenharia Biomédica do Departamento de Engenharia Elétrica, UNESP – Campus Ilha Solteira, constituído por 120 sensores resistivos, tipo Force Sensing Resistor (FSR), dispostos matricialmente em duas plataformas, e por circuitos de aquisição de dados, comunicação e interfaceamento. Com as informações obtidas, por meio do software é possível identificar deformidades na região plantar e locais desta região submetidos a forças elevadas. Foram feitos testes em um grupo de 30 voluntários com diferentes faixas etárias e diferentes graus de escoliose. Inicialmente os voluntários foram divididos em dois grupos, sendo que o grupo G2 (45-78 anos) apresentou valores de estabiliometria maiores quando comparados com o G1 (13-30 anos). De forma similar, foi segmentada a mesma população (N=30) em dois grupos, segundo o grau de escoliose, GrA (0-9°) e GrB (10-32°). O grupo GrB mostrou maiores valores de estabiliometria do que o GrA e foi possível determinar que quanto maior o grau de escoliose menor a dependência das variáveis de estabiliometria com a idade. / The foot is the main support organ of the human body that is constantly subjected to efforts to ensure the stability of the body. Analyzing the distribution of force in the plantar region of individuals, it is possible to infer about feet pathologies, postural and balance problems, among others. The study of foot force distribution is made with the baropodometer, an equipment composed by hardware and software systems. This work describes the baropodometer developed at the Instrumentation and Biomedical Engineering Laboratory at the Department of Electrical Engineering, UNESP – Ilha Solteira, composed of 120 resistive sensors (Force Sensing Resistor - FSR) arranged in matrix on two platforms. Furthermore, acquisition and communication boards and software made in LabVIEW were developed. With the information obtained, with the software it is possible to identify deformities in the plantar region and sites of this region subjected to high forces. Tests in 30 volunteers with different ages and different scoliosis angles were made. Firstly, the volunteers were divided into two groups according to ages. The second group G2 (45-78 years old) had higher stabilometry values than first group G1 (13-30 years old). Secondly, the 30 volunteers were divided in two groups according scoliosis angles, GrA (0-9°) e GrB (10-32°). The GrB group showed higher stabilometry values than the GrA group, and it was possible to determine that the higher the degree of scoliosis the lower the dependency of stabiliometry variables with the age.