Thermomechanical response

Thermomechanical response characteristics of ZrO/Ni functionally graded materials An experimental study to check model predictions... 

In the present investigation we are particularly interested in the thermomechanical response characteristics of the specimens under conditions of uniform through-the-thickness heat flow. Thus, the uniformity of surface heating is quite important. Figure 3 shows an example of the observed radial temperature distributions over the upper specimen surface upon heating. While the temperature gradually decreases from the center to the periphery of the specimen, the maximum temperature differential AT in the radial direction is small in comparison with the temperature at the center. For instance, =<0.11 and 0.03 after heating for 5 s... 

Elastic Deformation Due to High-Intensity Localized Heating. If plastic deformation is avoided, elastic deformation may still induce material cracking and/or failure. The thermomechanical response of an opaque material to high intensity localized heating has been considered. When strain rates are insufficiently high to induce internal heating (and deformations are small), the conduction solutions of the previous section may be combined with the classical equation of elastic stresses ... 

Pure Spot FSW. Awang et al. (Ref 23) presented some results on finite element modeling of FSSW using ABAQUS/Explicit (ABAQUS, Inc.) as a finite element solver. A three-dimensional (3-D) coupled thermal-stress model was used to calculate the thermomechanical response of the FSSW process. Adaptive meshing and advection schemes, which make it possible to maintain mesh quality under large deformations, were used to simulate the material flow and temperature distribution in the FSSW process. 

The finite element (FE) model of the FSSW process was done using ABAQUS/Explicit software. A 3-D dynamic fully coupled thermal-stress analysis was performed to obtain thermomechanical responses of the FSSW process. Two features in the FE package were deployed in order to obtain the results ... 

For engineering purposes, the most useful classification of polymers is based on their thermal (thermomechanical) response. Under this scheme, polymers are classified as thermoplastics or thermosets. As the name suggests, thermoplastic polymers soften and flow under the action of heat and pressure. Upon cooling, the polymer hardens and assumes the shape of the mold (container). Thermoplastics, when compounded with appropriate ingredients, can usually withstand several of these heating and cooling cycles without suffering any structural breakdown. This behavior is similar to that of candle wax. Examples of thermoplastic polymers are polyethylene, polystyrene, and nylon. 

Figure 3.7 Schematic showing the effect of moisture absorption on the thermomechanical response (DMTA, dynamic mechanical thermal analysis) of a resin, (Left) tan 8 (right) storage modulus dry/as-cured...

It is now well established that the thermomechanical response of glassy polymers and their composites is viscoelastic at temperatures near to, and above the glass transition temperature. Therefore, an accurate long term durability model at elevated temperatures for resins and reinforced plastics (FRP) must necessarily include viscoelastic behavior. This is especially true... 

Figure 20.4 Modulated force thermomechanical response for NR with frequency and temperature.

The predictions show that the same tendencies at specified locations are visible at location B, showing the expected order, that is, case 1 giving higher stress values than case 2. The results imply that the use of a longer fillet radius improves the thermomechanical response of the components as lower tensile values are obtained. In general, it is clearly demonstrated that the thermomechanically induced stress... 

Boyd, J.G. Lagoudas, D.C. Thermomechanical response of shape memory composites. J. Intelligent Material Systems and Structures, 5 (1994), pp. 333 346... 

In this chapter we will give a review of recent advances in understanding the nature of the nematic phase transition in LCEs [3-5]. In addition, this chapter explores the possibiUties of controlling the critical behaviour of the nematic transition and, thus, the type of thermomechanical response. In Sect. 1, the nature of the nematic transition will be briefly discussed for pure liquid crystals (LCs) and LCEs. Sections 2 and 3 focus on the application of two essential experimental techniques, high-resolution ac calorimetry and deuteron nuclear magnetic resonance ( H-NMR) spectroscopy, to these systems. Section 4 explains the nature of the nematic transition in LCEs as revealed by the two techniques. Section 5 is devoted to experimental studies that systematically explored the possibilities of tailoring the TM response of LCEs by a variation of the chemical composition and other parameters during the synthesis. 

Tailoring the Thermomechanical Response of LCEs hy Influencing the Critical Behaviour... 

Rozic B, Krause S, Finkehnarm H, Cordoyiannis G, Kutnjak Z (2010) Controlling the thermomechanical response of liquid-crystalline elastomers by influencing their critical behavior. Appl Phys Lett 96 111901... 

Melting, crystallization, and crystallinity studies on 2GT fibres have been reviewed in a paper on structure and thermomechanical responses of fibres. This study introduces the concept of a dynamic crystalline gel as a separate... 

Bieler.T. R., Jiang, H., Lehman, L. R,Kirkpatrick,T., Cotts,E. J., Influence of Sn Grain Size and Orientation on the Thermomechanical Response and Reliability of Pb-free Solder Joints, Electronic Components and Technology Conference, 2006, pp. 1462-1467. 

D. H. Kaelble, L. W. Crane and P. J. Dynes, "Morphology and Thermomechanical Response of CTBN Modified Epoxy Resins", to be published. 

Minor morphological differences, as between MR and NATSYN show up by their thermomechanical responses. Work on polymer chain conformations in bulk, 1968-to date, especially on fluorinated acrylics with B. McGarvay and W. Lee, on elastomeric dienes with H. Mark and K. Sato, and of entanglements in GRS witn R. Meyers, followed. These experiences were reviewed, with emphasis on the structural factors in rubber-like behavior at all phases of extension, in a chapter coauthored by T. L. Smith, on the Rupture of Elastomers in Liebowitz s treatise "Fracture , while later analyses focused on the effect of fillers in elastomers, the role of interfaces in composites, failure mechanisms in plastics as a function of morphology, and on resulting lessons for polymer engineering. 

C.S. Desai, J. Chia, T. Kundu, and J.L. Prince, Thermomechanical Response of Materials and Interfaces in Electronic Packaging Part 1—Unified Constitutive Model and Calibration and Part 2— Unified Constitutive Models, Validation and Design, Trans. ASME, Vol 119, 1997, p 294-300 and p 301-309... 

Figure 5.92. Reflected light image of a defect in cable insulation. The defect appears rougher in texture than the surrounding matrix (dotted outline) (A). Reflected light image of the thick section shown in (A) following three local thermal analysis cluster measurements using SThM (B). Intermittent contact mode AFM phase images of (C) the cross linked PE/EBA matrix and (D) the defect shown in (A). The defect is devoid of discrete EBA phases. The thermomechanical response of the heated probe in contact with the defect (solid curves) and matrix (dashed curves of [A]) are seen to melt at different temperatures (E). (From Bar and Meyers [170] used with permission of the MRS Bulletin.)...

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