Modulus of elasticity in tension

Poly vinylidene fluoride is polymerized under pressure at 25-150°C in an emulsion using a fluorinated surfactant to minimize chain transfer with the emulsifying agent. Ammonium persulfate is used as the initiator. The homopolymer is highly crystalline and melts at 170°C. It can be injection molded to produce articles with a tensile strength of 7000 psi (48 MPal. a modulus of elasticity in tension of 1.2 x 105 psi and a heat deflection of 3003F (149°C). 

In the ideal case of a Hookean body, the relationship between stress and strain is fully linear, and the body returns to its original shape and size, after the stress applied has been relieved. The proportionality between stress and strain is quantified by the modulus of elasticity (unit Pa). The proportionality factor under conditions of normal stress is called modulus of elasticity in tension or Young s modulus E), whereas that in pure shear is called modulus of elasticity in shear or modulus of rigidity (G). The relationships between E, G, shear stress, and strain are defined by ... 

Coefficient of linear expansion, 70 Modulus of elasticity in tension, 70 Impact resistance, 70 Tensile strength, 70 Roof tiles, 42... 

The modulus of elasticity in tension shown here is the quotient of the tension (ti) and the elongation (c) in the case of bar elongation with unhindered transverse shrinkage. It was determined in accordance with DIN 53457. 

Nominal tensile strain at the tensile strength the nominal temsile strain at the tensile strength, if the specimen breaks after yielding Modulus of elasticity in tension the ratio of stress difference to the corresponding strain difference. These strains are defined in the standard as being 0.05% and 0.25%. Also known as Young s modulus. This definition is not applicable to films (or rubber as noted earlier)... 

Figures 4.31 and 4.321 1 represent the tensile stress-strain curves and the polymer-cement ratio-elon tion (i.e., maximum tensile strain at failure) relationships of SBR-modified concretes respectively. As seen in these figures, as the polymer-cement ratio is raised, die modulus of elasticity in tension decreases, and the elongation increases and is 2 to 3 times greater than that of unmodified concrete. This is explained by considering that the polymer films formed in the concrete may effectively halt propagating microcracks through their high tensile strength and elongation.

Young s modulus, also referred to as elastic modulus, tensile modulus, or modulus of elasticity in tension is the ratio of stress-to-strain and is equal to the slope of a stress-strain diagram for the material. In the standard test method, ASTM D412, a force is apphed to a dog-bone-shaped sample of the cured adhesive. The force at elongation (strain) is measured. Most often, the elongation is 25-30% although for elastomeric materials it may be 100% or greater. 

Based on the stress-strain diagram the values tensile stress at yield cXy and tensile strength at maximum (7m as well as the associated normative yield strain and nominal strain 8tM or normative strain 8m at tensile strength as well as strain at break 8b can be calculated (Eqs. 4.6. 11). For completely recorded diagrams the nominal strain at break 8tB can be determined additionally (Eq. 4.12). Because of the dependence on software and test equipment, especially sampling rate, the tensile stress at break (Tb should not be used (Eq. 4.13). Due to the viscoelastic behaviour of the plastics modulus of elasticity in tension is determined as secant modulus between the strain limits of 0.05 % and 0.25 % (Eq. 4.14). If the transverse strain is recorded simultaneously using strain gauges Poisson ratio jl can be calculated (Eq. 4.15). 

In the Figures can be seen that modulus of elasticity in tension as well as tensile strength depend strongly on test temperature and degree of crystallinity. In the case of reinforced materials such as poly (butylene terephthalate) or polyamide the content of fibers has an essential influence on the level of properties. For polyamides such as PA 6 or PA 66 the moisture of specimen influences the level of modulus and strength additionally. It is of essential importance whether the tests are executed in dry or conditioned state of material. 

Fig. 4.15 Modulus of elasticity in tension in dependence on fiber content and moisture [08Els].

Fig. 4.18 Modulus of elasticity in tension of PA 6 (dry) in dependence on temperature [12Cam].

To illustrate the effect of modulus mismatch on structural performance consider the symmetrically repaired reinforced concrete prism shown in Fig. 6.4 and loaded axially in tension. The concrete has a modulus of elasticity in tension of 25 kN/mm. For material C ( t = 14 kN/mm ) the elastic stress induced in the concrete at mid-height of the prism will be 2.5 times that in the repair material at the same position. Conversely for material D ( , = 43 kN/mm ) the elastic stress carried by the repair material is now 1.5 times that... 

E n. (1) SI abbreviation for prefix exa-. (2) Symbol commonly used for modulus of elasticity in tension (See modulus of elasticity). 

Young s modulus Young s modulus, also called the Young s modulus of elasticity, is the modulus of elasticity in tension. It is the ratio of stress in a material to its deformation. Young s modulus is the ratio of normal stress to corresponding strain for tensile or compressive stresses at less than the proportional limit of the material. 

Polymer Modulus of Elasticity in Tension (ASTM D638) (10 psi)... 

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