Elastic behavior, steel

The properties of the lamina constituents, the fibers and the matrix, have been only briefly discussed so far. Their stress-strain behavior is typified as one of the four classes depicted in Figure 1-8. Fibers generally exhibit linear elastic behavior, although reinforcing steel bars in concrete are more nearly elastic-pertectly plastic. Aluminum, as well as... 

This property of viscoelasticity is possessed by all plastics to some degree, and dictates that while plastics have solid-like characteristics, they also have liquid-like characteristics (Figure 1.2). This mechanical behavior is important to understand. It is basically the mechanical behavior in which the relationships between stress and strain are time dependent for plastic, as opposed to the classical elastic behavior of steel in which deformation and recovery both occur instantaneously on application and removal of stress.1... 

However, no real material shows either ideal elastic behavior or pure viscous flow. Some materials, for example, steel, obey Hooke s law over a wide range of stress and strain, but no material responds without inertial effects. Similarly, the behavior of some fluids, like water, approximate Newtonian response. Typical deviations from linear elastic response are shown by rubber elasticity and viscoelasticity. 

These considerations have been accomplished in an example to model the SPS behavior of graphitic elements that are inserted between the two stainless steel rams used in the model 515S system (Sumitomo), which is schematically shown in Fig. 6.30 [42]. The geometry of the graphitic elements has been designed in such a way that it not necessary to consider the effect of vertical interfaces between them. As a result, the horizontal contact resistances can be excluded in the mathematical models. A 2D model in cylindrical coordinates based on the usual enthalpy conservation equation that takes into account the Joule heat generation is developed, which is coupled to density current balances expressed in terms of the RMS portion of the electric potential and the mechanic equilibrium equations due to elastic behavior and thermal expansion of the materials. Thermophysical properties of... 

The assumption at the basis of the calculation are the linear-elastic behavior of aU materials, the cross-beam sections remaining plain, and the absence of deformation (perfect bonding) between concrete and steel, and between concrete andFRP. 

Figures 6.5 and 6.6 show the so called transition point Nt where elastic and plastic components intersects. Beyond A, it is the elastic component of strain that dominates and control the fatigue life of the material whereas below N, the plastic strain prevails. This actually means that beyond Nt high cycle fatigue becomes the dominant failure mode and the Basquin line may sufficiently well represent the S-N fatigue behavior of the material. Below N instead, low cycle fatigue is the failure mode of the material and Mason-Coffin relationship based on strain amplitude is needed. In the surroundings of N, it is necessary to consider both components. It is worth noting how for the softer steel Man-Ten the transition Nt from plastic to elastic behavior can be placed at about 2 10" cycles while for the harder steel RQC-100 it already happens at about 10 cycles. At 10" cycles the plastic component of strain is only a mere 1/30 of the elastic one. For the aluminum alloy this transition occurs even earlier at about 100 cycles. At about 10 cycles the total curve coincides with the elastic component. The coordinates of Nt can be found by putting Ep = and recalling Eq. (6.10) it yields...

Upright cylindrical steel tanks (non-base-isolated) supported directly on the grotmd or on the foundation may be designed with a behavior factor q that represents a quasi-elastic behavior, i.e., q < 1.5. More specifically, a value of = 1 is recommended for the convective motion where negligible dissipation of energy occurs, whereas a value of = 1.5 (quasi-elastic behavior) is recommended for the impulsive motion. 

RTR filament-wound pipe is, however, an anisotropic material. That is, its material properties, such as its modulus of elasticity and ultimate strength, are different in each of the principal directions of hoop and longitude. It is here where the design approaches for steel and RTR pipe part company [Fig. 4-2(c)]. This behavior is a result of the construction of filament-wound RTR pipe. 

Since blast-resistant design is based on structural response beyond elastic limits into the inelastic range, buildings should be carefully designed in a manner that minimizes stress concentrations, brittle behavior, and abrupt failures. Some of the significant design considerations for steel and reinforced concrete blast-resistant structures are briefly summarized in this section. 

Materials are modeled classically as either viscous, such as water or molasses, or elastic in nature, such as steel beams or metal springs. In general, polymers are complex materials that behave in a combined response to strain with both viscous and elastic characteristics. Under conditions where the material exhibits both viscous and elastic rheological behavior, the polymers are described as viscoelastic. That is, polymers have substantial viscous and elastic characteristics when strained. 

The upper piston, rlt is equipped with a water cooling system, b, and carries a gage in a tension ring accurate to 10 3 mm. The gage shows the position of the upper piston. c % relative to the cylinder, e it reflects the height of the specimen and variation of the seals. The elastic and thermal behavior of the steel parts is negligible. 

During several decades, stainless steel was the most frequently used alloy for joint replacements. At present. Co-base alloys have taken first place, and about 70% of all orthopedic implants are made from Co-Cr alloys. During the past 20 years, titanium and its alloys have become more important due to their bone-like elasticity and their excellent biological behavior. 

The method is also applicable to other materials that exhibit a barely discemable transition from elastic to inelastic behavior such as aluminum and high-strength steel. This expectation was verified with specimens made of 2024-T4 aluminum, 6061-T651 aluminum, and ASTM A709 HPS 690W Cu-Ni steel. 

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