Design material parameter

MEMS devices have to meet certain criteria with respect to their functional parameters, for example, a scale factor, offset of the output value, temperature coefficient, nonlinearity, hysteresis, noise, resolution, and cross sensitivities, which characterize the system s performance. In addition, we are interested in the reliability, yield, and cost of the devices. The set of functional parameters depends on a set of model parameters, consisting of processing, material, and geometrical parameters. All model parameters act as input parameters for the design procedure as well as for the manufacturing process. Material parameters are influenced by... 

Fig. 4.1.9 Schematic chart of the dependencies relevant to robust design. The only allowed input model parameters are geometry and material parameters, which are correlated with processing effects...

Spigulis, J., et al., 1997. Glowing optical fiber designs and parameters. In Krumins, A., et al. (Eds.), Optical Inorganic Dielectric Materials and Devices. SPIE, Riga, Latvia, pp. 231—236. 

Even if the appropriate models and model solving tools were readily available, the necessary material parameters are not well established—even for well-studied materials such as sihcones and acrylics. The inability to fiiUy model a system does not allow for a full exploration of design tradeoffs and optimizations. In particular. 

Designing ceramic machinery, especial ceramic extruders, requires knowledge of certain process parameters such as throughput, pressure, force and power requirement. Everyday practice shows that such quantities are highly dependent on the rheological properties and, hence, the material parameters of the compounds. 

For the purpose of a qualitative evaluation of a complex extruder design it often may be sufficient to carry out the simulation with reduced physics, that is to pass on wall slip and to perform the simulation for example with a constant low viscosity. But the more exact the real conditions should be followed, the more activities to locate the material parameters have to be spent. A reasonable access to avoid disaccords in the interpretation of the simulations on complex geometries is to calibrate the physical model on a simple nozzle. On such a basic structure it is possible to compare the measured pressures with the calculates values and to customize the complex physics of Bingham or wall slip parameters. 

Another factor of anisotropic design analysis is greater dependence of stress distributions on materials properties. For isotropic materials, whether elastic, viscoelastic, etc., static values often result in stress fields which are independent of material stiffness properties. In part, this is due to the fact that Poisson s ratio is the only material parameter appearing in the compatibility equations for stress. This parameter does not vary widely between materials. However, the compatibility equations in stress for anisotropic materials depend on ratios of Young s moduli for different material axes, and this can introduce a strong dependence of stress on material stiffness. This approach can be used in component design, but the product and material design analysis become more closely related. 

To effectively prevent denaturation of protein in spray-dried powders, one needs to be able to pinpoint at what stage of drying the protein was denatured. A model that can predict the timing and degree of denaturation as a function of process parameters as well as material properties (e.g., presence of protectant solids) will greatly help design process and material parameters that allow production of minimally denatured protein powders. 

A design engineer must be thoroughly familiar with the material plastic, both reinforced and unreinforced, in all of its possible variants and nuances, must be well-versed in the use of modem aids such as databases and must know when to consult external experts. Decades of practice are needed to dimension molding designs so as to accommodate all material parameters. 

In the field of polymers, the potential of simulation software has not yet been fully exploited. The standard numeric models for polymers are nowadays far from precise and the corresponding determination of material parameters is not well defined. It can be assumed that tailored testing in combination with better simulation tools would improve the early phase of the design process enormously. 

Design basics for the use of FRP profiles in civil engineering applications are provided in ASCE (1984) and EUROCOMP (1996), but these two documents do not have model code-like status. Additionally, there exist design manuals published by the manufacturers of pultruded FRP profiles, e.g. FiberlineComposites (2003). Beside the design concept, all the necessary material parameters and associated material safety factors are given in these manuals. 

The polyesteresterketone is specially designed material meeting the stringent requirements from the point of view of heat resistance, inflammability, products combustions and chemical resistance [218, 219], Vic-trex owns the unique combination of properties thermal characteristics and combustion parameters quite imusual for thermoplastic materials, high stability to effect of different dissolvents and other fluids [220, 221],... 

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