Thermomechanical, modeling

Over the last decade considerable effort of the tectonics community has been directed towards the development of thermomechanical models that describe the collisional history and the internal dynamics of orogenic belts and continental plateaus (e.g., Beaumont et al. 2001, 2004 Koons et al. 2002). These models are commonly tested against thermobarometric, thermochronologic, and geochronologic data. However, by definition, these data sets only provide constraints on rates of rock uplift or exhumation the surface response to tectonic... 

THERMOMECHANICAL MODELLING FOR FREEZING OF SOLUTE SATURATED SOIL... 

Thermomechanical Modelling for Preezing of Solute Saturated Soil 335... 

Thermomechanical model of freezing soil by use of the theory of mixtures. In Proceedings of the 6th Finnish Mechanics Days, Aalto, J., and Salmi, T., (eds), 1997, 1-26. 

Wanne, T. Johansson. 2003. Aspb Pillar Stability Experiment. Coupled 3D thermomechanical modeling. Preliminary results. 

THERMOMECHANICAL MODELING OF THE MICROSTRUCTURED POROUS MEDIA WITH INCLUSIONS... 

C.M. Chen and R. Kovacevic, Thermomechanical Modelling and Porce Analysis of Prichon Shr Welding by the Pinite Element Method, Proc. Inst. Mech. Eng., Part C J. Mech. Eng. ScL, Vol 218,2003, p509-519... 

Part I - Thermothermomechanical modeling. Composites Part A, 37 (9), 1296-1308. 

Thermomechanical models for FRP materials were first developed in the 1980s. One of the first thermomechanical models for FRP materials was introduced by Springer in 1984 [1], where the degradation of mechanical properties was empirically related to the mass loss. In 1985, Chen et al. [2] added a mechanical model to the thermochemical model presented by Griffis et al. in 1981 [3] mechanical properties at several specified temperature points were assembled into a finite element formulation. Griffis et al. [4] introduced an updated version of Chen s model in 1986, whereby an extrapolation process was used to obtain the data in a higher temperature range. 

In 1992, McManus and Springer [5, 6] presented a thermomechanical model that considered the interaction between mechanically induced stresses and pressures created by the decomposition of gases within the pyrolysis front. Again, temperature-dependent mechanical properties were determined at several specified temperature points as stepped functions. The issue of degradation of material properties at elevated temperatures was considered in Dao and Asaro s [7] thermo-mechanical model in 1999. The degradation curves used in the model were, once again, obtained by curve fitting of limited experimental data. 

In 2004, Gibson et al. [10] then presented an upgraded version by adding a new mechanical model. A function that assumes the relaxation intensity is normally distributed over the transition temperature was used to fit the temperature-dependent Young s modulus. Furthermore, in order to consider the resin decomposition, each mechanical property was modified by a power law factor. Predictions of mechanical responses based on the thermomechanical models were also performed by Bausano et al. [11] and Halverson et al. [12]. Mechanical properties were correlated to temperatures through dynamic mechanical analysis (DMA) but no special temperature-dependent mechanical property models were developed. 

The above-mentioned thermomechanical models only consider the elastic behavior of materials. Boyd et al. [13] reported on compression creep rapture tests performed on unidirectional laminates of E-glass/vinylester composites subjected to a combined compressive load and one-sided heating. Models were developed to describe the thermoviscoelasticity of the material as a function of time and temperature. In their work, the temperature-dependent mechanical properties were determined by fitting the Ramberg-Osgood equations and the temperature profiles were estimated by a transient 2D thermal analysis in ANSYS 9.0. 

Fig. 20 Thermomechanical model for covalently crosslinked SMPs. (a) Schematic diagram of the micromechanics foundation of the 3-D SMP constitutive model (1). Existence of two extreme phases in the polymer is assumed. The diagram represents a polymer in the glass tiansition state with a predominant active phase (b) In the 1-D model, the frozen fraction (pf = Lf (T) /L(T) is defined as a physical internal state variable that is related to the extent of the glass transition, (c) Frozen fraction, (j>f (T), as a function of temperature, derived from curve fitting of the modified recovery strain curve divided by the predeformation strain, (d) Prediction of the free strain recovery responses during heating for polymers predeformed at different levels. Fig. (a) and (b) reprinted with permission from ref. [92], Copyright 2005, Materials Research Society, Warrendale, PA. Fig. (c) and (d) reprinted from [71], Copyright 2006, with permission from Elsevier.

Nonequilibrium thermomechanical models for two-phase flow in three-phase fixed-bed reactors... 

Iliuta I, Hamidipour M, Larachi F. Non-equilibrium thermomechanical modeling of liquid drainage/imbibition in trickle beds. AIChE J. 2012 58 3123. 

Figure 26.5 Components of an SOFC stack (a) and the stresses in the components (b) at operating temperature modeled with a coupled thermomechanical model using SOFC-MP and MSC Marc.

The flow along the fiber direction can be modeled as a channel flow (the viscous flow between two parallel plates). Loss and Springer (29) validated thermomechanical models, including the chemorheological behavior of resin and resin flow models. 

Thermomechanical modeling of ionconducting membrane for oxygen separation. /. Ear. Ceram. Soc., 28, 793-801. 

The material constitutive model plays an important role in the development of thermomechanical models for microelectronic packaging assembly. Under thermomechanical loading, solder alloy undergoes elastic and inelastic de-... 

The development of thermomechanical models typically involves (a) the development of constitutive models for the solder alloy and other materials in the packaging assembly, (b) the development of geometry models to represent the solder interconnects and the packaging assembly, and (c) the development of failure predictive models for the various material systems in the assembly. The thermomechanical models, when subjected to thermal excursions seen dixring accelerated qualifications or during field-use, will identify the location of failure, mode of failixre, and time to failure in various parts of the packaging assembly. Prior to usage, the models should be validated with experimental test data. 

The thermomechanical models can be validated through various approaches, and in this section, only the most popular approaches are discussed. One approach is to design, fabricate, and assemble a test vehicle, and to subject the test vehicle to accelerated thermal cycling. The test vehicle typically consists of a dummy die or... 

Up-front thermomechanical modeling and physics-based reliability prediction of lead-free solder joints could save significant amount of cost and time in microsystem product develop-... 

Fuel thermomechanical models consist of a code for normal operation, which predicts the initial fuel conditions before an accident (strain, fuel-to-sheath heat transfer coefficient, gas release, initial temperatures, etc.), and a transient thermomechanical code for accidents. The latter includes submodels for fuel failure mechanisms due to fuel sheath strain, beryllium braze penetration, sheath embrittlement due to oxidation, athermal strain and excessive fuel energy content. Because of the need to predict the dose for each accident, the models must be able to estimate the percentage of fuel that fails in an accident (if any), and the release of fission products to the channel. 

Under certain circumstances, such as a large LOCA combined with a loss of emergency core coolant injection, the pressure tube will overheat and (depending on the internal pressure) sag or strain into contact with the calandria tube. This requires models of the pressure tube thermomechanical transient behaviour, to predict the extent of deformation and the pressure tube temperature and internal pressure when/if it contacts the calandria tube. Separate channel thermomechanical models have been used to-date, using somewhat artificial boundary conditions (fixed steam flow rate) the system thermohydraulic codes now incorporate this capability, allowing more realistic predictions of the distribution of flow to each channel. 

The coupling between the thermomechanical model of the process and the crystallization kinetics is generally... 

The analysis of structure development is based on the combination of a thermomechanical model and of an experimental study of structures and morphologies inside the films. 

Thermomechanical Model Taking into account the operating conditions, a general model of... 

Modeling Much work has been devoted to the introduction of crystallization into thermomechanical models of the injection-molding process [64, 68, 69, 138-149]. The conservation equations (mass, momentum, and energy) were first solved by the finite difference method [138-143, 146, 147] for a simplified flow geometry, either 2D [138,139], or one-dimensional (ID) as a result of the lubrication approximation [140-143,... 

---