Static modulus

An instrument for measuring the mechanical properties of rubbers in relation to their use as materials for the absorption and isolation of vibration. These properties are resilience, modulus (static and dynamic), kinetic energy, creep and set. The introduction of an improved version has recently been announced. 

G(0) low-frequency limit of the storage modulus (static modulus)... 

Complex/dynamic viscosity Creep compliance Relaxation modulus Static/dynamic force Temperature... 

Another characteristics feature of the glass transition is the associated change in the modulus. The stress, elongation, is related to the strain, the force applied to a material by the modulus. Conventionally there are two approaches to the measurement of the modulus static and dynamic. The static method involves measurement of the stress strain profile and from the slope of the curve the elastic modulus can be determined. The dynamic method subjects the sample to a periodic oscillation and explores the variation of the amplitude and phase of the response of the sample as a function of temperature. A small sample of the test material is subjected to displacement as shown in Figure 7.3. 

The Yerseley Mechanical Oscillograph supplied by ATS FAAR measures, according to ASTM D945 [142], the mechanical properties of rubber vulcanisations in the small range of deformation that characterises many technical applications. These properties include resilience, dynamic modulus, static modulus, kinetic energy, creep, and set under a given force. 

Modulus, static Ratio of stress-to-strain under static conditions. It is calculated from static S-S tests in shear, tension, or compression. Expressed in force per unit area. 

Plant Bending strength, MPa Cold crushing strength, MPa Elastic modulus (static), GPa Elastic modulus (dynamic), GPa Thermal coefficient of linear expansion x 10 , degree Thermomechanical strains, MPa R, degree... 

Table 3. Mechanical properties of the hybrid fiber-reinforced composites c,- static flexural strength, - dynamic flexural strength, - static flexural Young s modulus, - dynamic flexural Young s modulus, - static fracture toughness, - dynamics fracture toughness. For batch numbering, see Table 2.

The radiation and temperature dependent mechanical properties of viscoelastic materials (modulus and loss) are of great interest throughout the plastics, polymer, and rubber from initial design to routine production. There are a number of laboratory research instruments are available to determine these properties. All these hardness tests conducted on polymeric materials involve the penetration of the sample under consideration by loaded spheres or other geometric shapes [1]. Most of these tests are to some extent arbitrary because the penetration of an indenter into viscoelastic material increases with time. For example, standard durometer test (the "Shore A") is widely used to measure the static "hardness" or resistance to indentation. However, it does not measure basic material properties, and its results depend on the specimen geometry (it is difficult to make available the identity of the initial position of the devices on cylinder or spherical surfaces while measuring) and test conditions, and some arbitrary time must be selected to compare different materials. 

Abstract. This paper presents results from quantum molecular dynamics Simula tions applied to catalytic reactions, focusing on ethylene polymerization by metallocene catalysts. The entire reaction path could be monitored, showing the full molecular dynamics of the reaction. Detailed information on, e.g., the importance of the so-called agostic interaction could be obtained. Also presented are results of static simulations of the Car-Parrinello type, applied to orthorhombic crystalline polyethylene. These simulations for the first time led to a first principles value for the ultimate Young s modulus of a synthetic polymer with demonstrated basis set convergence, taking into account the full three-dimensional structure of the crystal. 

Some tests, while undergoing deformation, are usually referred to as static in that they are performed at slow speeds or low cycles. Examples of these tests are stretch modulus, ultimate tensile, and elongation to break, ie, a measure of total energy capabiUties or mpture phenomena. 

Young s modulus can be deterrnined by measuring the stress—strain response (static modulus), by measuring the resonant frequency of the body... 

Basire and Frctigny [72J to determine the sample modulus quasi-statically for viscous contacts. 

The shear modulus of a material can be determined by a static torsion test or by a dynamic test employing a torsional pendulum or an oscillatory rheometer. The maximum short-term shear stress (strength) of a material can also be determined from a punch shear test. 

Second, the creep modulus, also known as the apparent modulus or viscous modulus when graphed on log-log paper, is normally a straight line and lends itself to extrapolation for longer periods of time. The apparent modulus should be differentiated from the modulus given in the data sheets, which is an instantaneous or static value derived from the testing machine, per ASTM D 638. 

In structural applications for plastics, which generally include those in which the product has to resist substantial static and/or dynamic loads, it may appear that one of the problem design areas for many plastics is their low modulus of elasticity. The moduli of unfilled plastics are usually under 1 x 106 psi (6.9 x 103 MPa) as compared to materials such as metals and ceramics where the range is usually 10 to 40 x 106 psi (6.9 to 28 x 104 MPa). However with reinforced plastics (RPs) the high moduli of metals are reached and even surpassed as summarized in Fig. 2-6. 

Frictional forces are not proportional to load-friction increases with increasing speed, and the static coefficient of friction is lower than its dynamic one. When two viscoelastic low-modulus materials are run against each other, additional inconsistencies result. 

Polymer Dynamic shear modulus (frequency > 1 Hz) S/MPa Quasi-static Young s modulus (frequency 0.01 Hz) E/MPa Ratio 3S/E... 

The important elastic properties of a material undergoing deformation under static tension are stiffness, elastic strength and resilience. For a material obeying Hooke s law, the modulus of elasticity, E (= o/e), can be taken to be a measure of its stiffness. The elastic... 

Besides the static scaling relations, scaling of dynamic properties such as viscosity rj and equilibrium modulus Ge [16,34], see Eqs. 1-7 and 1-8, is also predicted. The equilibrium modulus can be extrapolated from dynamic experiments, but it actually is a static property [38]. 

It is interesting to note here that the cluster mass distribution and the relaxation modulus G(t) at the LST scale with cluster mass and with time, respectively, while all other variables (dynamic and static) scale with the distance from pc in the vicinity of the gel point. 

Being a very sensitive quantity, however, the relative energy part of the modulus is different for some of the samples, if calculated from static or dynamic data, respectively. (For the calculation method, compare ref. 2J3, K ) Table III gives the values for the relative energy part. ore(j u/ored the ener9Y part calculated from stress-strain measurements Gy/G is the corresponding number obtained from dynamic data at 0.5 Hz. 

Changes in phase have important consequences for other thermodynamic properties and thus geophysical implications. For example, the bulk modulus at any pressurep in the static limit is given by the value of V(d2(//dV2) (at that pressure) for CaO this increases markedly across the phase boundary. 

Response of a material under static or dynamic load is governed by the stress-strain relationship. A typical stress-strain diagram for concrete is shown in Figure 5.3. As the fibers of a material are deformed, stress in the material is changed in accordance with its stress-strain diagram. In the elastic region, stress increases linearly with increasing strain for most steels. This relation is quantified by the modulus of elasticity of the material. 

For steel, the modulus of elasticity is the same in the elastic region and yield plateau for static and dynamic response. In the strain hardening region the slope of the stress-strain curve is different for static and dynamic response, although this difference is not important for most structural design applications. 

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