Strength multiaxial

There are many different equipment options avaQable to suit specific product needs including continuous winders for pipe, multiaxis winders for pressure vessels, and simple lathe-type winders for tanks and large pipe. Specialty machines combine a chopped reinforcement with continuous fibers for tank walls and large-diameter pipe where both stiffness and tensQe strength are required. Textile braiders have also been adapted for use as continuous... 

G. P. Sendecky), A Brief Survey of Empirical Multiaxial Strength Criteria for Composites, In Composite Materials Testing and Design (Second Conference), H. T. Corten (Chairman), Anaheim, Caiifomia, 20-22 April 1971, ASTM STP 497, American Society for Testing and Materials, 1972, pp. 41-51. 

In addition to strength and WOF of FMs, the elastic behavior of these architectures should be considered. Simple brick models were proposed to accurately predict elastic properties of FMs [1, 24], Figure 1.8 shows the elastic modulus versus orientation for uniaxially aligned Si3N4/BN FMs with experimentally measured values, indicating that there is very good agreement between experiment and prediction. This prediction can be used for FMs with multiaxial architectures. 

Four-circle geometry. Since the crystal rotates around three orthogonal axes, this instrument geometry may seem inappropriate to measurements at very low temperatures. In fact, several good mechanical solutions have been found. Here the main constraints come from the absence of a nodal plane (or axis) for the multiaxial sample rotations, from space limitations due to the internal diameter of the x cradle, from the mechanical strength of the x cradle, which must hold the cryostat without deformation, and from the power of motors, which must be able to rotate heavy parts and to drag more or less flexible links. 

Here F, denotes the tensile strength of the material, Fc is the compressive strength, and Ybc represents equal biaxial compression strength of the material. The reader is directed to Palko25 where the specific forms of B and A are presented. This model is termed a three-parameter model, referring to the three material strength parameters (F FC, and Ybc) used to characterize the model. Failure is defined when / = 0, and the multiaxial criterion is completely defined in the six-dimensional stress space. 

ISO 4600 details a ball or pin impression method for determining the ESCR. In this procedure, a hole of specified diameter is drilled in the plastic. An oversized ball or pin is inserted into the hole, and the polymer is exposed to a stress cracking agent. The applied deformation, given by the diameter of the ball or pin, is constant. The test is multiaxial, relatively easy to perform, and with not very well-defined specimens, and the influence of the surface is limited. Drawbacks are the small testing surface and the undefined stress state. After exposure, tensile or flexural tests may be performed on the specimens. This leads to the determination of either the residual tensile strength or the residual deformation at break. 

An impact modifier is a rubber phase dispersed in particulate form throughout the matrix of a polymer solid. Unlike plasticizers, the rubber particles retain their intrinsic properties as a separate phase. The glass transition temperature of the parent matrix is not lowered by the addition of an impact modifier. The rubber particles do two things to the parent matrix phase (2,3,4) they act as stress concentrators (i.e., a large strain will start in the matrix near the interface) and they enhance the multi-axiality in stress. As multiaxial tensile strength near the interface further enhances dilatation, which shortens the mechanical relaxation time, the otherwise brittle polymer solid of the matrix will undergo plastic deformation in the vicinities of the rubber particles. 

Figure 16.11 Change of multiaxial impact strength during outdoor weathering in Florida...

Figure 16.12 Multiaxial impact strength (ISO 6603-2) of ASA and ABS after heat ageing at 90 °C...

The mechanical properties of solid propellants are discussed by Kelly [25]. In the U S.A. the methods are based on instructions worked out by a Joint-Army-Navy-Air Force (JANAF) Physical Properties Panel and include uniaxial and multiaxial measurements of mechanical strength. 

Lamon J. Ceramics reliability statistical analysis of multiaxial failure using the Weibull approach and the multiaxial elemental strength model. Journal of the TVmeiican Ceramic Society 1990 73(8) 2204-2212. 

The amount of data generated under global (external) multiaxial loading can be used as reference to discuss the influence of the main design parameters on the fatigue strength... 

In spite of the importance that notches and stress concentrations can have in the design of structural parts, their influence on multiaxial fatigue strength has rarely been investigated [10,15,16,29,32,33]. It is difficult to draw general design indications from the few data available however, from at least one of the papers cited, some interesting conclusions can be obtained. 

Susuki I. Static and fatigue strength properties of composite laminates under in-plane biaxial loadings. In Proceedings of 5th international conference on biaxial/multiaxial fatigue and fracture 1997. pp. 79—89. Cracow, Poland. 

Philippidis TP, Vassilopoulos AP. Fatigue strength prediction under multiaxial stress. 

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