Uniform tension

Irwin [23] developed an expression for the mode I stress intensity factor around an elliptical crack embedded in an infinite elastic solid subjected to uniform tension. The most general formulation is given by ... 

The achievement of rubbering is also dependent upon the condition of the textile material. Unless a perfectly flat uniformly tensioned sheet is passed through the fabric nip, the calender operator must make frequent adjustments to the roll setting to prevent either fabric crushing or loose topping. 

Mechanical properties of the interfacial layer between two fluid phases can be tension expressed in terms of those of a geometrical surface of uniform tension called the surface tension. 

Under the effect of uniform hydrostatj.c pressure and uniform tension, the effective bulk modulus, K = 1/P, and effective shear modulus, p, are calculated. The result is... 

Before the x-ray method is examined in any detail, it is advisable to consider first a more general subject, namely, the difference between applied stress and residual stress, and to gain a clear idea of what these terms mean. Consider a metal bar deformed elastically, for example in uniform tension. The applied stress is given simply by the applied force per unit area of cross section. If the external force is removed, the stress disappears, and the bar regains its initial stress-free dimensions. On the other hand, there are certain operations that can be performed on a metal part, which will leave it in a stressed condition even after all external forces have been removed. This stress, which persists in the absence of external force, is called residual stress. 

Figure 7 Variation of the normalized strain energy release rate widi aa and in a graded orthotropic medium under uniform tension ko = 1, i = 0.3, oo) = po, So = iri a/Eo.

Figures 7 and 8 respectively show the effect of a and 6 and a and kq on the normalized strain energy release rate in an orthotropic FGM with a crack of length 2a located along the x axis. The problem is one of mixed-mode, the external load is a uniform tension po perpendicular to the crack plane and Qo is the strain energy release rate for the corresponding homogeneous isotropic medium for which a = 0, kq = 1. = 1.= 0.3 [18].

The test data overpage were gathered in a uniaxial tension test on a polycrystalline alumina specimen. The gage section of the specimen (section of specimen under uniform tension) was cylindrical with a length of 50 mm and a diameter of 3 mm. 

A notched thick plate of Al Oj, containing a through-thickness internal crack is broken in uniform tension (mode I). The fracture stress was 12 MPa and the critical crack size (2c) was 60 mm. The Young s modulus and Poisson s ratio of Al Oj are 400 GPa and 0.26, respectively. 

Due to the requirement of exact control of elastic yams in producing fabrics with repeatable stretch recovery and modulus, care should be taken to store the yams as close to the conditions of manufacturing as possible, particularly for spandex. Lycra, and XLA and shape memory fiber. Proper warping for the elastic yams is essential. Uniform tension and draft of yams are suggested for each package. All yam beams should be in an identical set with the same length of yams. 

Consider, for example, the assessment of a simple steel member in a lattice girder subject to uniform tension. It is first necessary to define a critical stress above which the tie would be considered to have failed. Using elastic theory this would be tlic yield stress of the steel, The permissible stress is then obtained by dividing the critical stress by a safety factor which is Judged to be appropriate. For oxiitnple in B.S. 449 Table 2, the permissible stress of tension members of steel to H.S. 4360 Grade 43 is 16.S and its yield stress is 247 The... 

When tension devices are used, the unsupported strand length can be reduced to 8 ft. or less, depending on coil size. The shorter distance, coupled with uniform tension, and aided by fact that strip fan-out is accomplished ahead of the tension device in a free-Ioop state, results in improved sidewall condition. 

Many potential users of this type of tensioning device are reluctant to purchase this design today because surface finish of the strip is becoming more and more critical, and this type of unit has the potential to mar a bright finish if the wipers are not properly maintained. Another deficiency of this type of unit is that it is not possible to operate with any form of slip-core rewinding because this unit is not capable of metering strip flow. However, even with these possible drawbacks, there is no other device that will produce a more uniform tension across the face of the coil and, with care, not mar most material surfaces. 

This programme was presented last year (ref. 2). The purpose of TERFIS 5 tests carried out in 1996 was to quantify the influence of residual stresses on crack initiation and growth in weldments. They were obtained on stainless steel 316 L tubes where a defect was machined in a welded joint. The tubes were submitted to a low uniform tension (29 Mpa) and to thermal stocks (ex in the case of a circunferential defect AT in the thickness 180°C and 10 cycles in the case of a semi-elliptic defect AT in the thickness 300°C and 1500 cycles). 

At this stage, it should be noted that Kj refers to a crack loaded in uniform tension, or Mode I. Other crack loading modes exists as shown in Figure 14.6, and Eq. (19) may be more completely defined as ... 

All pass back rollers must rotate freely and tow tension in the first passes must be adjusted to ensure that the fiber band does not come into contact the floor of the oven. The fiber band must be of uniform thickness, with no gaps and must have a uniform tension. The inlet and outlet fiber speeds in oxidation control the mpul of the opf. The uniformity of colour across the first and second passes of the oxidized PAN tow band will be a good indication of uniform temperature distribution which must be within 2°C. The control of the level of oxidation can be ascertained by measuring the final oxidized density. 

Geodesic-isotensoid contour n. In filament-wound, reinforced-plastic pressure vessels, a dome contour in which the filaments are placed on geodesic paths so that the filaments will experience uniform tensions throughout their lengths under pressure loading. laac MD, Ishal O (2005) Engineering mechanics of composite materials. Oxford University Press, UK. 

Figure 1. Plexiglas theta specimen. The figure on the right shows the specimen in crossed polarizers while loaded by diametral forces P on the rim. The middle web is stretched in uniform tension a.

Adjust the head straps to achieve snug, uniform tension on the mask. If only extreme tension on the straps will seal the respirator, report this to the Supervisor. A mask with uncomfortably tight straps rapidly becomes obnoxious to the wearer. 29 CFR 1910.134 (g)(1)(A) states "Personnel with facial hair that comes between the sealing surface of the facepiece and the face or that interferes with valve function shall not be... 

The surface of any fluid will be in a state of uniform tension if the fluid surface satisfies the following conditions ... 

A uniformly stretched rubber membrane is similar in many respects to a soap film, or the interface between two fluids. It has a uniform tension and the thickness of the membrane is small compared with the dimensions of the surface area. The analysis of section 5.2, which derives the Laplace-Young equation for a fluid interface or soap film, applies equally to a uniformly stretched membrane with a transverse pressure load that is perpendicular to the surface. So the Laplace-Young equation for the membrane is... 

As for the legitimacy of the principle of tension. Young relies simply on capillary phenomena being able to be attributed to mutual attractions of only the surface particles hquid surfaces must be made up of curves of the nature of the catenary, which are supposed to be the result of a uniform tension in a surface which resists the pressure of a fluid. Finahy he tries to show that one can hnd a cause of normal pressures and tractions only in the play of attractions and repulsions of molecules, and he leaves thus in doubt if the tension acmally exists, or if, by normal forces, the things occur as under the influence from a tension. 

Taking a very simple example, the stress intensity factor for a single edge crack growing normal to the surface (0 = 90°) of a plate (which is much wider than the crack) in uniform tension is given by Equation (2) where applied stress and a is the crack length [2]. 

---