Elastic properties of wire rope-Determination of Elastic Modulus of Steel Wire Ropes for Computer Simulation

Any assembly of steel wires spun into a helical formation, either as a strand or wire rope when subjected to a tensile load can extend in three separate phases, depending on the magnitude of the applied load. There are also other factors which produce rope extension, which are very small and can normally be ignored. At the commencement of loading a new rope, extension is created by the bedding down of the assembled wires with a corresponding reduction in overall diameter. This reduction in diameter is accommodated by a lengthening of the helical lay. When sufficiently large bearing areas have been generated on adjacent wires to withstand the circumferential compressive loads, this mechanically created extension ceases and the extension in Phase 2 commences.

Elastic properties of wire rope

Elastic properties of wire rope

Elastic properties of wire rope

Elastic properties of wire rope

Elastic properties of wire rope

In this paper, a numerical simulation method is supposed to simulate the thermo-mechanical behaviors of SMP Elasticc the finite Elastix software of MSC Marc, which is good Nurse practitoner jobs clermont fla simulating the thermo-mechanical behaviors of viscous elastic material. The pressure of the rope against the sheave also causes distortion and flattening of the rope structure. RE: Elastic modulus of wire rope It will depend a lot Elastic properties of wire rope the lay up and twist. Floating sheaves or specially designed fleet angle compensating devices may also be employed to reduce the fleet angle effect. RE: Elastic modulus of wire rope You might want to repost this on one of the civil engineering forums. All Rights Reserved. These rope constructions will rotate excessively with one end free to rotate, and the rope will unlay and distort and be easily damaged with a loss of rope breaking force. For a given rope construction, the torque factor can be expressed as a proportion of the rope diameter and this has been done below. To reduce the amount of twist to an acceptable level, the fleet angle should be limited to 2. Applied Mechanics and Materials Volume

Private tutor ged. Elastic modulus of wire rope

Unlike suspension cables, climbing ropes are not designed to be continuously under roe. It is possible however, that the use of a swivel will have See free videos of naked people adverse affect on rope performance and may, in some cases, damage the wire rope. Privacy Policy. Molnar, N. It is estimated that the local pressures at these contact points may be as high as five times those calculated. The fibers in loosely woven Hollow-Braid rope are all tope roughly the same angle to the Elastic properties of wire rope and this angle is quite small. At the Sheave Where a fleet angle exists as the rope enters a sheave, it initially makes contact with the sheave flange. These rope constructions, when used in a reeving system with one end free to rotate, will have a high Elastic properties of wire rope of rotation. For Nylon the comparable value is about 0. Construction Description Basic strand for propdrties concentric cable, relatively stiff in larger diameters, offers the least stretch. Value Shackles.

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  • Modulus of elasticity of steel wire rope elastic modulus is a characteristic value, which is important not only for users of the steel rope, but also for designers of machines and machinery that are equipped with the steel wire rope.
  • The configuration and method of manufacture combined with the proper selection of material when designed for a specific purpose enables a wire rope or cable to transmit forces, motion and energy in some predetermined manner and to some desired end.
  • Any assembly of steel wires spun into a helical formation, either as a strand or wire rope when subjected to a tensile load can extend in three separate phases, depending on the magnitude of the applied load.
  • The following discussion relates to conventional 6- or 8-strand ropes that have either a fiber or steel core.
  • Download this document in PDF format.
  • Rope is familiar and ubiquitous — and we assume it will behave like, well, Rope.

Log In. Cheers Greg Locock New here? Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action. Click Here to join Eng-Tips and talk with other members! Already a Member? Join your peers on the Internet's largest technical engineering professional community. It's easy to join and it's free. Register now while it's still free! Already a member? Close this window and log in.

Are you an Engineering professional? Join Eng-Tips Forums! Join Us! By joining you are opting in to receive e-mail. Promoting, selling, recruiting, coursework and thesis posting is forbidden. Students Click Here. Related Projects. This question is automotive-related only because I'm working on a trailer that will haul a race car. I don't have an M. I need a ballpark value of modulus of elasticity in tension, of course! You might want to repost this on one of the civil engineering forums.

It will depend a lot on the lay up and twist. I presume the 6 19 is number of yarns and number of strands per yarn. I can't answer your question, but I would think whoever does, needs the twist data. You need to contact the mfgr of the wire rope, and ask for typical data. The data will not be very reproducible from batch to batch of rope.

The stretch-vs. If the wire is wound onto a winch drum it will similarly change its stretch vs. Kind of begs the question of where in the middle of "hauling a race car" is this rope being applied, since most hauling applications use trailer hitches to make the connection. There ought not be any self-created structure that's being loaded under use. That's just asking for lawsuits if it ever breaks.

My old MacWhyte Handbook has some numbers see enclosed. It might be on a winch designed to haul a car onto the trailer, even if the car is broken. It might operate a tail gate or ramps or tilt mechanism or dual level mechanism.

BT and Greg gave the best advice in my opinion. Red Flag This Post Please let us know here why this post is inappropriate.

Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework. Simulation on the Stator of an Electric Motor: Electric motors and generators produce vibrations and noise associated with many physical mechanisms. This study looks at the vibrations and noise produced by the transient electromagnetic forces on the stator of a permanent magnet motor.

Download Now. Simulation is an increasingly valuable tool across the product design workflow, but not all simulations are equal. We set out to determine how engineers and product designers make use of specialized analyses, how they incorporate nonlinear simulation into their work and how they rate the available software.

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Elastic modulus of wire rope Elastic modulus of wire rope This question is automotive-related only because I'm working on a trailer that will haul a race car. RE: Elastic modulus of wire rope You might want to repost this on one of the civil engineering forums. RE: Elastic modulus of wire rope It will depend a lot on the lay up and twist. RE: Elastic modulus of wire rope Kind of begs the question of where in the middle of "hauling a race car" is this rope being applied, since most hauling applications use trailer hitches to make the connection.

RE: Elastic modulus of wire rope the smaller cable on my come-along sinks into the cable wound on the drum before doing anything useful RE: Elastic modulus of wire rope It might be on a winch designed to haul a car onto the trailer, even if the car is broken.

Resources Simulation on the Stator of an Electric Motor: Electric motors and generators produce vibrations and noise associated with many physical mechanisms. Download Now Simulation is an increasingly valuable tool across the product design workflow, but not all simulations are equal.

Properties of Extension of Steel Wire Ropes Any assembly of steel wires spun into a helical formation, either as a strand or wire rope when subjected to a tensile load can extend in three separate phases, depending on the magnitude of the applied load. What is rarely known is that this is inherited from early recognition that Right Hand laid Hemp was stronger than Left Hand laid Hemp. Even now, fifty years later, I can close my eyes and savor the smell and the feel of new, tarred hemp rope. Because of the fact that broken wire ends do not porcupine, they are not as noticeable as they are in non-preformed ropes. Although elasticity is highly desirable in some applications, e. For estimating this stretch the value of one-half percent, or.

Elastic properties of wire rope

Elastic properties of wire rope. Wire and Cable Stretch Characteristics - Modulus of Elasticity - Break Load

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Any assembly of steel wires spun into a helical formation, either as a strand or wire rope when subjected to a tensile load can extend in three separate phases, depending on the magnitude of the applied load. There are also other factors which produce rope extension, which are very small and can normally be ignored.

At the commencement of loading a new rope, extension is created by the bedding down of the assembled wires with a corresponding reduction in overall diameter. This reduction in diameter is accommodated by a lengthening of the helical lay. When sufficiently large bearing areas have been generated on adjacent wires to withstand the circumferential compressive loads, this mechanically created extension ceases and the extension in Phase 2 commences. The Initial Extension of any rope cannot be accurately determined by calculation and has no elastic properties.

The practical value of this characteristic depends upon many factors, the most important being the type and construction of rope, the range of loads and the number and frequency of the cycles of operation. It is not possible to quote exact values for the various constructions of rope in use, but the following approximate values may be employed to give reasonably accurate results.

Following Phase 1, the rope extends in a manner which complies approximately with Hookes Law stress is proportional to strain until the limit of proportionality or elastic limit is reached.

The Modulus of Elasticity also varies with different rope constructions, but generally increases as the cross-sectional area of steel increases. By using the values given, it is possible to make a reasonable estimate of elastic extension, but if greater accuracy is required, it is advisable to carry out a modulus test on an actual sample of the rope.

As rope users will find it difficult to calculate the actual metallic steel area, the values can be found in the Wire Rope Users Manual or obtained from Bridon Engineering. The permanent, non-elastic extension of the steel caused by tensile loads exceeding the yield point of the material.

If the load exceeds the Limit of Proportionality, the rate of extension will accelerate as the load is increased until a loading is reached at which continuous extension will commence, causing the wire rope to fracture without any further increase of load.

The change will be an increase in length if the temperature rises and a decrease in length if the temperature falls. Extension Due to Rotation The elongation caused by a free rope end being allowed to rotate. Extension Due to Wear The elongation due to inter-wire wear which reduces the cross-sectional area of steel and produces extra constructional extension. Example: What will be the total elongation of a ft.

In addition to bending stresses experienced by wire ropes operating over sheaves or pulleys, ropes are also subjected to radial pressure as they make contact with the sheave. When a rope passes over a sheave, the load on the sheave bearing results from the tension in the rope and the angle of rope contact.

It is independent of the diameter of the sheave. Assuming that the rope is supported in a well fitting groove, then the pressure between the rope and the groove is dependent upon the rope tension and diameter, but is independent of the arc of contact. It must be realized that this method of estimation of pressure assumes that the area of contact of the rope in the groove is on the full rope diameter, whereas in fact only the crowns of the outer wires are actually in contact with the groove.

It is estimated that the local pressures at these contact points may be as high as five times those calculated. If the pressure is high, the compressive strength of the material in the groove may be insufficient to prevent excessive wear and indentation, and this in turn will damage the outer wires of the rope and effect its working life. As with bending stresses, stresses due to radial pressure increase as the diameter of the sheave decreases. Although high bending stresses generally call for the use of flexible rope constructions having relatively small diameter outer wires, these have less ability to withstand heavy pressures than do the larger wires in the less flexible constructions.

If the calculated pressures are too high for the particular material chosen for the sheaves or drums or indentations are being experienced, consideration should be given to an increase in sheave or drum diameter. Such a modification would not only reduce the groove pressure, but would also improve the fatigue life of the rope.

The pressure of the rope against the sheave also causes distortion and flattening of the rope structure. Recommended pulley hardness: Brinell for Mn steel or equivalent alloy steel. Industry standards provide minimum design factors allowed for certain rope applications. Some typical minimum design factors follow:. Bend fatigue testing of ropes usually consists of cycling a length of rope over a sheave while the rope is under a constant tension. As part of their ongoing development program, BRIDON has tested literally thousands of ropes in this manner over the years on their own in-house design bend testing equipment.

Through this work, BRIDON has been able to compare the effects of rope construction, tensile strength, lay direction, sheave size, groove profile and tensile loading on bend fatigue performance under ideal operating conditions. At the same time it has been possible to compare rope life to discard criteria e.

As part of the exercise, it has also been possible to establish the residual breaking strength of the rope at discard level of deterioration. What needs to be recognized, however, is that very few ropes operate under these controlled operating conditions, making it very difficult to use this base information when attempting to predict rope life under other conditions.

Other influencing factors, such as dynamic loading, differential loads in the cycle, fleet angle, reeving arrangement, type of spooling on the drum, change in rope direction, sheave alignment, sheave size and groove profile, can have an equally dramatic effect on rope performance.

However, the benefit of such testing can be particularly helpful to the rope manufacturer when developing new or improving existing products. If designers or operators of equipment are seeking optimum rope performance or regard bending fatigue life as a key factor in the operation of equipment, such information can be provided by BRIDON for guidance purposes. Wire ropes are manufactured slightly larger than the nominal diameter.

The maximum allowable oversize tolerances provided by industry standards are shown in the following table:.

Typical minimum bending ratios sheave or drum dia. Under certain circumstances it may be necessary to use a swivel in a lifting system to prevent rotation of the load. This is typically done for employee safety considerations. It is possible however, that the use of a swivel will have an adverse affect on rope performance and may, in some cases, damage the wire rope.

There are many types of accessories available that incorporate different types and degrees of rotation- preventing swivels. The swivel may be either an independent accessory or an integral part of a lifting device, such as a crane block with a swivel hook. A typical independent accessory is a ball bearing anti-friction swivel. There are also headache balls with swivel hooks. The type of swivel that causes the most concern from the standpoint of the wire rope is the independent anti-friction swivel that attaches directly to the rope.

The purpose of using a swivel in a lifting system is to prevent rotation of the load. This then allows the wire rope to rotate. Excessive rope rotation can damage a wire rope. To assist in determining whether or not a swivel should be used in the lifting system, the following recommendations should be considered.

It must also be recognized that the rotation characteristics of different types and constructions of wire rope vary considerably. The following types and constructions of wire rope are grouped according to their rotation characteristics. Wire rope constructions having very high rotation characteristics should not be used with a swivel under any circumstances.

These rope constructions will rotate excessively with one end free to rotate, and the rope will unlay and distort and be easily damaged with a loss of rope breaking force. Wire rope constructions having high rotation characteristics when used in single part reeving may require a swivel in the system to prevent rotation in certain operating conditions.

However, this should be done only when employee safety is the issue. These rope constructions, when used in a reeving system with one end free to rotate, will have a high level of rotation. This will cause the rope to unlay and, to some degree, distortion of the rope will occur. The ropes in this Group are designed with an inner rope that is laid in the opposite direction to the outer strands to provide a medium resistance to rotation.

Ropes with medium rotation characteristics are used with a swivel in single part reeving applications. However, a swivel is not recommended for multiple part hoisting applications or in any application where the swivel is not necessary for safety reasons.

If it is necessary to use a swivel, the rope must be operating at a design factor of 5 or greater, must not be shock loaded and must be inspected daily by a qualified person for distortion.

It should be noted that if a swivel is used on conjunction with Group 3a ropes, rope service life might be reduced due to increased internal wear between the outer strands and the inner rope. Wire ropes having low rotation characteristics used in either single or multiple part reeving may be used with a swivel. The reason for this is that the ropes will exhibit very little, if any, rotation when used at the proper design factor.

Application parameters, such as a fleet angle, may induce turn into a wire rope that can be relieved by the use of a swivel. However, if the application does not induce any turn into the rope, or if a swivel is not beneficial to the performance of the rope, the swivel may not be necessary. Note: When using a swivel with any wire rope, frequent inspection of the rope is necessary.

The rope should not be shock loaded or overloaded. Of all the factors which have some influence on the winding of a rope on a smooth drum, the fleet angle, arguably, has the greatest effect.

Fleet angle is usually defined as the included angle between two lines: one which extends from a fixed sheave to the flange of a drum, and the other which extends from the same fixed sheave to the drum in a line perpendicular to the axis of the drum see illustration.

If the drum incorporates helical grooving, the helix angle of the groove needs to be added or subtracted from the fleet angle as described above to determine the actual fleet angle experienced by the rope. When spooling rope onto a drum, it is generally recommended that the fleet angle is limited to between 0. If the fleet angle is too small, i. If the rope is allowed to pile up, it will eventually roll away from the flange, creating a shock load in both the rope and the structure of the mechanism, an undesirable and unsafe operating condition.

Excessively high fleet angles will return the rope across the drum prematurely, creating gaps between wraps of rope close to the flanges, as well as increasing the pressure on the rope at the cross-over positions. Floating sheaves or specially designed fleet angle compensating devices may also be employed to reduce the fleet angle effect. Where a fleet angle exists as the rope enters a sheave, it initially makes contact with the sheave flange.

As the rope continues to pass through the sheave it moves down the flange until it sits in the bottom of the groove. In doing so, even when under tension, the rope will actually roll, as well as slide. As a result of the rolling action, the rope is twisted, i. As the fleet angle increases, so does the amount of twist. To reduce the amount of twist to an acceptable level, the fleet angle should be limited to 2.

However, for some crane and hoist applications, it is recognized that for practical reasons. It is not always possible to comply with these general recommendations, in which case, the rope life could be affected. The problem of torsional instability in crane hoist ropes would not exist if the ropes could be perfectly torque balanced under load.

For a given rope construction, the torque factor can be expressed as a proportion of the rope diameter and this has been done below. Variation with rope construction is relatively small and hence the scope for dramatically changing the stability of a hoisting system is limited. Nevertheless, the choice of the correct rope can have a deciding influence, especially in systems which are operating close to the critical limit.

It should be noted that the rope torque referred to here is purely that due to tensile loading. No account is taken of the possible residual torque due, for example, to rope manufacture or installation procedures. Torsional Stability and the Cabling Graph are two methods which can be used to determine torsional stability or the tendency of the rope to cable.

Elastic properties of wire rope

Elastic properties of wire rope

Elastic properties of wire rope