Cord Tension

The selection of cord materials for belts and plies in a tire and the associated physical locations lend themselves to further FEA analysis. If one takes an inflated nonbelted tire, the ply cords, whether they are in a single-ply casing or multiple-bias-ply construction, will assume a configuration that minimizes strain within the composite. The resulting cord path is termed the neutral contour. Belted tires introduce a restriction to the inflated diameter of the tire, and the neutral contour or plyline of such systems is consequently altered. 

FIGURE 14.12 PlyUne definition. Purdy s equation defines ideal inflated or natural shape for thin-film structure. C = curvature of the plyline, pc = radius from the center of the axle to the center of the plyline or tire centerline, and p = radius from the center of the axle to the center plyline width. 

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Cord tension variation 250 N per total width both in calendering direction and across... 

Cord tension as low as possible, but sufficient to keep cord distribution... 

By applying a sufficient high cord tension this can be avoided. However, cord tension might cause some elongation. The duration of application of high cord tension has to be as short as possible in order to avoid creep. The complete upstream and downstream of the calender is mainly dedicated to maintain the preset cord tension. In order to keep the cord tension as low as possible the tension can be set in 3-5 steps. One (or two) in the textile upstream, one in the calender area, and... 

Only in the calender area the cord tension is high enough to resist the pressure caused by the mbber flow in the calender nip region. Therefore, a constant cord density can be maintained by means of locally high cord tension. 

Typical inflated cord tension plots for a truck tire are shown in Figure 14.13. In an unloaded state the cord tension for the belts tends to be at the tire centerline, and the ply tension is greatest at the point corresponding to the sidewall location however, on application of a load to the inflated tire and consequent deflection, the cord tensions increase at the belt edges away from the centerline and in the bead zone. As reviewed earlier, these two regions tend to be the failure zones in a tire construction (Figure 14.14). 

The belts consist of a synthetic mbber backing, reinforced with glass cord tension members and protected by a nylon fabric coating on the teeth. The size range available is listed. 

This inward force has a real agent, namely, a tension of the cord, which is applied to the body. The same cord acts on the pin with a force, which has the same magnitude as that of the centripetal one but opposite direction. This force has the same physical origin, (deformation of cord) and it is called the centrifugal force. The term centrifugal means literally fleeing a center . Centripetal and centrifugal forces always form a pair of action and reaction and they are applied to different parts of the system. In our case these parts are a small body and a pin. 

Before closing the action of the rifle, position the trip wire or pull cord, making sure there is enough slack to avoid tension on the trigger. 

Unlabeled Uses Low back pain, spasticity associated with multiple sclerosis or spinal cord injury, tension headaches, trigeminal neuralgia... 

The components that are supported by cords or fabric can be treated on-line easily by using a system of pulleys. This, unforfunately, is not yet possible for unsupported components, such as inner liner and other low-tension materials. ... 

Arrow is a slender shaft with a pointed head used as a missile which is propelled by releasing the tension of the string of a long bow. A bow consists of a strip of wood or other elastic material with a tension cord connecting both end. The bow and arrow constituted one of the earliest weapons. A later development of the long bow was the crossbow, also known as arbalest (qv). Eventually both were replaced by firearms... 

Skeletal muscle spasms are used to describe the increased tension often seen in skeletal muscle after certain musculoskeletal injuries and inflammation (muscle strains, nerve root impingements, etc.) occur.20,96 This tension is involuntary, so the patient is unable to relax the muscle. Spasms differ from spasticity because spasms typically arise from an orthopedic injury to a musculoskeletal structure or peripheral nerve root rather than an injury to the CNS. Likewise, muscle spasms are often a continuous, tonic contraction of specific muscles rather than the velocity-dependent increase in stretch reflex activity commonly associated with spasticity. The exact reasons for muscle spasms are poorly understood. According to some authorities, muscle spasms occur because a vicious cycle is created when the initial injury causes muscular pain and spasm, which increases afferent nociceptive input to the spinal cord, further exciting the alpha motor neuron to cause more spasms, and so on.61,96 Other experts believe that muscle spasms occur because of a complex protective mechanism, whereby muscular contractions are intended to support an injured vertebral structure or peripheral joint.96 Regardless of the exact reason, tonic contraction of the affected muscle is often quite painful because of the buildup of pain-mediating metabolites (e.g., lactate). 

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