Environmental condition thermal loading

Systems used for accident mitigation should be designed to withstand the maximum loads, stresses and environmental conditions for the accidents analysed. This should be assessed by separate analyses covering environmental conditions (i.e. temperature, humidity or chemical environment) and thermal and mechanical loads on plant structures and components. 

Cables should be of adequate rating for the load, having regard to environmental conditions, e.g. under or in thermal insulation or in hot environments. 

Dynamic mechanical thermal analysis (DMTA) has also been used by Brinson, et al.,t l to determine the suitability of the technique for evaluating damage in the adhesive bond from the viscoelastic properties of bonded beams and for evaluating the effects of various environmental conditions and various surface treatments. The authors considered that if the bond becomes damaged (either adhesive and/or interphase) due to excessive load, fatigue, moisture, or corrosion, it would seem likely that dissipation mechanisms or loss modulus and tan 5 would change. Therefore, they used DMTA to measure the viscoelastic properties of beams with simulated flaws and beams taken from lap specimens, which had been exposed to humidity and/or corrosion for extended periods. 

To form a strong, integrally bonded, load-bearing structure, the surface of the adherend should be pretreated before application of the adhesive this is vital if good environmental or thermal durability is required. Such a procedure ensures that the surface is in as clean a condition as possible, removing weak boundary layers which could adversely affect the performance of the resultant joint. 

Severe loss of ductility of a metal (or alloy) loss of load carrying capacity of a metal or alloy the severe loss of ductility or toughness or both, of a material, usually a metal or alloy. Many forms of embrittlement can lead to brittle fracture and many can occur during thermal treatment or elevated-temperature service (thermally induced embrittlement). Some of these forms of embrittlement, which affect steels, include blue brittleness, 885 °F (475 °C) embrittlement, quench-age embrittlement, sigma-phase embrittlement, strain-age embrittlement, temper embrittlement, tempered martensite embrittlement, and thermal embrittlement. In addition, steels and other metals and alloys can be embrittled by environmental conditions (environmentally assisted embrittlement). Forms of environmental embrittlement include acid embrittlement, caustic embrittlement, corrosion embrittlement, creep-rupture embrittlement, hydrogen embrittlement, bquid metal embrittlement, neutron embrittlement, solder embrittlement, sobd metal embrittlement, and stress-corrosion cracking. 

The ranges of properties in plastics encompasses all types of environmental and load conditions, each with its own individual, yet broad, range of properties (Fig. 1-9). These properties can take into consideration wear resistance, integral color, impact resistance, transparency, energy absorption, ductility, thermal and sound insulation, weight, and so forth. There is unfortunately no one plastic that can meet all maximum properties. Therefore, the designer has different options, such as developing a compromise because many product requirements provide options, particularly if cost is of prime importance. 

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