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- Chernoray, Valery, 1975, et al.
(författare)
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Projects in Applied Mechanics 2017
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The course TME131 Project in Applied Mechanics is a mandatory course within the AppliedMechanics Masters programme at Chalmers. The course was carried out during springsemester 2017. In total 7 projects were carried out, and 4 of these are collected here.
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| 2. |
- Danvind, Jonas, et al.
(författare)
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Calibration of a constitutive model for diffusive moisture transport in wood using data from X-ray CT-scanning and digital speckle photography
- 2004
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Ingår i: 5th Conference on Timber drying for value-added prducts, COST action E15 "advances in drying of wood". ; , s. 210-218
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An unsteady-state diffusion model is applied for studying wood drying below the fibre saturation point. The moisture diffusion coefficient in Fick's law for Norway spruce under isothermal drying conditions is determined. Using X-ray CT-scanning and Digital Speckle Photography, the wood density and moisture content are obtained in the radial direction of the wood samples. An optimization scheme is used to minimize the difference between observed and computed moisture content in order to calibrate the values of a set of parameters describing the diffusion coefficient. In this study the values of the parameters for a parameterization of Arrhenius' type are determined. The general idea discussed, however, is not limited to a specific model, butcan be used for a wide class of parameter identification problems. The results show a good agreement between observed and computed moisture content and it is concluded that the numerical realization of the optimization scheme works well. Nevertheless, the value of the diffusion coefficient is somewhat higher than expected. This is likely the consequence of a permeable coating of the samples.
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| 3. |
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| 4. |
- Eriksson, John, 1973, et al.
(författare)
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A Mass-Transport Model for Drying Wood under Isothermal Conditions
- 2005
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Ingår i: 9th international IUFRO wood drying conference, Nanjing, China, August 21-26, 2005. ; 1:1, s. 51-56
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Mass transport in wood during drying is often described in terms of different periods. Depending on the current moisture content (MC) and the structure of the wood, the driving forces behind the mass transport are essentially different. Above a certain level of MC, the fibres are partially saturated and the transport of liquid (free) water occurs mainly as a consequence of capillary action. On the other hand, below the fibre saturation point, bound water within the cell walls is conveyed by diffusion, and water vapour in the lumen moves under influence of pressures. In this contribution, a unified model is presented that takes into account the transport of the different water phases. Simulation of the drying of a Norway spruce sample from about 135% to 7% MC is carried out using the finite element method (FEM). The resulting mean MC is compared with experimental observations obtained from X-ray Computed Tomography showing reasonable agreement. Possible simplifications in the model are briefly discussed as well as some aspects of the numerical implementation.
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| 5. |
- Irfan, Muhammad, 1986, et al.
(författare)
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Constrained Lagrangian Formulation for Modelling and Analysis of Transmission Synchronizers
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- An engineering model of a generic synchronizer is considered. The generic synchronizeris modeled consisting of the selector sleeve with engaging teeth and frictional cone, thesynchronizing ring with blocker and the gearwheel with engaging teeth. It is assumed thatfor the sleeve and synchronizing ring translational and rotational motions are feasible, forthe gearwheel only rotational motion is feasible. The motion of the generic synchronizer isperformed under the external and internal loads. The external loads comprise the vehicleresistance torque and the control force applied to the sleeve and the drag torque due to theclutch. The internal loads comprise the forces and torques arises due to interactionbetween the sleeve, the synchronizing ring, the gearwheel as well as oil splash during thesynchronization process. A feasible synchronization process of a generic synchronizer isdivided into four main phases: pre-synchronization, main synchronization, blockertransition (indexing for the ring), and engagement. Pre-synchronization and blockertransition are further divided into several sub-phases. The generic synchronizer is fullyparametrized and together with description of all phases constitutes kinematics ofsynchronization process in question.Due to the nature of synchronization process in transmission system a motion of asynchronizer mechanism is subjected to unilateral or/and bilateral constraints imposed ongeneralized coordinates or/and generalized velocities of the synchronizer. ConstrainedLagrangian Formalism (CLF) has been proposed as an approach for developingmathematical and computational models of a generic synchronizer dynamics. The CLFgives possibility to formulate direct dynamics, semi-inverse dynamics and inversedynamics problems for a generic synchronizer in unified and efficient way. It is shown thatCLF can be promising and useful for advanced dynamic analysis of the existingsynchronizer mechanisms and to design novel optimized ones.In the present report mathematical and computational models of a generic synchronizerwith five degrees of freedom have been developed using CLF. Application of CLF on themodelling of the synchronization process gives system of differential-algebraic equations(DAE). Analysis of the generic synchronizer performance diagrams has shown that the CLFbased model is able to predict the synchronization process characteristics reasonably well.The developed model has been validated by using measurement data from test rig at CVAB Scania. Performance of the generic synchronizer is also analyzed in case of drivelinevibrations. Sensitivity analysis of the synchronizer mechanism performance with respect tocone angle, coefficient of friction, maximum value of shift force and rate of applying shiftforce has been done.Next, the developed models will be used to get further insight into synchronizer design andits performance diagrams with aid of global sensitivity analysis and Pareto optimization.
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| 6. |
- Irfan, Muhammad, 1986, et al.
(författare)
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VERIFICATION OF A TRANSMISSION SYNCHRONIZATION MODEL
- 2017
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Ingår i: Svenska Mekanikdagarna, Uppsala, 12-13 juni 2017. ; , s. 48-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A computational model of the gearshiftingmechanism may speed up the development of anew gearboxes. However, such model should beverified against other models as well as validatedagainst experiments to ensure reasonableaccuracy. In this contribution, results from the previousdeveloped mathematical model of a genericsynchronizer (gearshifting mechanism) againstthe model developed at Scania is presented. The mathematicalmodel is based on constrained Lagrangianformalism (CLF) and the generic synchronizer isconsist of engaging sleeve, synchronizer ring andthe gearwheel with dimensions relevant to that ofa heavy truck.
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