Single Strand Wire Research Articles

Effect of internal defect on the low-cycle bending fatigue behavior of a single-strand wire rope

• The low-cycle bending fatigue behavior of a defective wire rope is analyzed. • The minimum fatigue life of the wire rope occurs near the defective area. • The internal defect increases the risk of stress yielding of the wire rope. • The internal defect reduces the minimum fatigue life of the wire rope. • An increment in radial position of defect causes a worse performance of the rope. In order to explore the evolution rules and failure mechanism of bending fatigue behavior of a defective single-strand wire rope under cyclic bending load, the influence of average stress and elasto-plasticity on the bending fatigue behavior is considered in this paper. Based on the characteristics of constant amplitude cyclic load, a finite element analysis model of the low-cycle bending fatigue behavior of the single-strand wire rope with an internal defect is established. Then the fatigue lives of the defective rope and non-defective rope are compared, and the influence of the defect’s radial position on the bending fatigue behavior of the rope is discussed. The results show that under the cyclic bending load, the minimum fatigue life of the defective rope in the cross section occurs in the defective area, while that of the non-defective rope lies in the interwire contact area. The defect changes the fatigue life distribution of the single-strand wire rope, and improves the fatigue life locally but reduces the rope’s bearing capacity. Additionally, a larger distance between the defect and neutral layer causes an earlier stress yielding in defective area and makes a greater risk of fatigue failure.

In vivo biofilm formation on stainless steel bonded retainers during different oral health-care regimens.

Retention wires permanently bonded to the anterior teeth are used after orthodontic treatment to prevent the teeth from relapsing to pre-treatment positions. A disadvantage of bonded retainers is biofilm accumulation on the wires, which produces a higher incidence of gingival recession, increased pocket depth and bleeding on probing. This study compares in vivo biofilm formation on single-strand and multi-strand retention wires with different oral health-care regimens. Two-centimetre wires were placed in brackets that were bonded to the buccal side of the first molars and second premolars in the upper arches of 22 volunteers. Volunteers used a selected toothpaste with or without the additional use of a mouthrinse containing essential oils. Brushing was performed manually. Regimens were maintained for 1 week, after which the wires were removed and the oral biofilm was collected to quantify the number of organisms and their viability, determine the microbial composition and visualize the bacteria by electron microscopy. A 6-week washout period was employed between regimens. Biofilm formation was reduced on single-strand wires compared with multi-strand wires; bacteria were observed to adhere between the strands. The use of antibacterial toothpastes marginally reduced the amount of biofilm on both wire types, but significantly reduced the viability of the biofilm organisms. Additional use of the mouthrinse did not result in significant changes in biofilm amount or viability. However, major shifts in biofilm composition were induced by combining a stannous fluoride- or triclosan-containing toothpaste with the mouthrinse. These shifts can be tentatively attributed to small changes in bacterial cell surface hydrophobicity after the adsorption of the toothpaste components, which stimulate bacterial adhesion to the hydrophobic oil, as illustrated for a Streptococcus mutans strain.

Biofilm formation on stainless steel and gold wires for bonded retainers in vitro and in vivo and their susceptibility to oral antimicrobials

Bonded retainers are used in orthodontics to maintain treatment result. Retention wires are prone to biofilm formation and cause gingival recession, bleeding on probing and increased pocket depths near bonded retainers. In this study, we compare in vitro and in vivo biofilm formation on different wires used for bonded retainers and the susceptibility of in vitro biofilms to oral antimicrobials. Orthodontic wires were exposed to saliva, and in vitro biofilm formation was evaluated using plate counting and live/dead staining, together with effects of exposure to toothpaste slurry alone or followed by antimicrobial mouthrinse application. Wires were also placed intra-orally for 72 h in human volunteers and undisturbed biofilm formation was compared by plate counting and live/dead staining, as well as by denaturing gradient gel electrophoresis for compositional differences in biofilms. Single-strand wires attracted only slightly less biofilm in vitro than multi-strand wires. Biofilms on stainless steel single-strand wires however, were much more susceptible to antimicrobials from toothpaste slurries and mouthrinses than on single-strand gold wires and biofilms on multi-strand wires. Also, in vivo significantly less biofilm was found on single-strand than on multi-strand wires. Microbial composition of biofilms was more dependent on the volunteer involved than on wire type. Biofilms on single-strand stainless steel wires attract less biofilm in vitro and are more susceptible to antimicrobials than on multi-strand wires. Also in vivo, single-strand wires attract less biofilm than multi-strand ones. Use of single-strand wires is preferred over multi-strand wires, not because they attract less biofilm, but because biofilms on single-strand wires are not protected against antimicrobials as in crevices and niches as on multi-strand wires.

Braided cerclage wires: A biomechanical study

Background One of the drawbacks that makes many surgeons reluctant to use cerclage wires is the risk of periosteal vascular compromise. A new, easily applied braided wire configuration has been developed to improve mechanical wire gripping and to decrease the contact area between the hardware and the bony surface. Materials and methods Braided wires with two diameters (1 mm and 1.5 mm) were compared to single-strand and double-strand wire configurations. The biomechanical properties, peak and elongation loads, and wire pressure imprint points of this new configuration were evaluated in the current study. Results The braided wire was found to have the same peak load as the double-strand wire ( P = 0.315) and more than twice the peak load than the single-strand wire ( P = 0.0001), but a much shorter elongation peak than the other two. The imprint test showed that the braided wire has an interrupted dotted pattern compared to the continuous circular one that characterises the single-strand and double-strand wires, indicating less potential damage to the bone. Conclusions The braided cerclage wire may decrease the extent of insult to the bone by decreasing the contact area between the hardware and the bony surface and by enhancing stability by reducing the elongation peak, affording increased fracture fixation stability.

A Method for Stabilizing a Lingual Fixed Retainer in Place Prior to Bonding

The objective of this article is to present a simple technique for stabilizing a lingual fixed retainer wire in place with good adaptation to the teeth surfaces and checking for occlusal interferences prior to the bonding procedure. Bonding of an upper or lower fixed lingual retainer using stainless steel wires of different sizes and shapes is a common orthodontic procedure. The retainer can be constructed in a dental laboratory, made at chair side, or it can be purchased in prefabricated form. All three ways of creating a fixed retainer are acceptable. However, the method of holding the retainer wire in place adjacent to the lingual surfaces of the teeth before proceeding with the bonding process remains a problem for some practitioners. The lingual fixed retainer was fabricated using three pieces of .010" steel ligature wire which were twisted into a single strand wire. Another four to five 0.010" pieces of steel ligature wires were twisted in the same way to serve as an anchor wire from the labial side of the teeth. The retainer wire was bonded using the foible composite. The technique presented here for stabilizing the retainer wire prior to bonding provides good stabilization, adaptation, and proper positioning of the retainer wire while eliminating contamination of etched surfaces which might arise during wire positioning before bonding. This technique also allows the clinician the opportunity to check the occlusion and adjust the retainer wire to avoid occlusal interference prior to bonding maxillary retainers. This same clinical strategy can be used to stabilize wires for splinting periodontally affected teeth and traumatized teeth.

Cobalt Chromium Sublaminar Wires for Spinal Deformity Surgery

Biomechanical analysis and retrospective chart review. To determine the mechanical properties of cobalt chromium alloy wires and review the clinical application of the wires as sublaminar implants to correct spinal deformity. Sublaminar wires are commonly used as anchors in spinal deformity surgery. In stainless steel instrumentation systems, single strand wires (Luque wires) may be retightened over time to take advantage of stress relaxation while correcting spinal deformity. Because of the mechanical properties of titanium, solid titanium wires are not used as sublaminar wires. Cobalt chromium alloy is a titanium compatible alloy that can be twisted in a similar fashion to stainless steel sublaminar wires. Comparative tensile tests were performed using cobalt chromium alloy wires and Luque stainless steel wires. In addition, 22 consecutive posterior spinal fusions for idiopathic scoliosis were performed using cobalt chromium alloy wires as sublaminar implants. Yield and ultimate tensile loads for the cobalt chromium alloy wires are on average 66% (P < 0.001) and 60% (P < 0.001) higher, respectively, than those for the steel wires. Mean preoperative thoracic curve for patients with idiopathic scoliosis was 56 degrees +/- 15 degrees , which corrected to 19 degrees +/- 11 degrees (67% correction, P < 0.001) when cobalt chromium alloy wires were used as sublaminar implants. Mean preoperative lumbar curve was 52 degrees +/- 14 degrees , which corrected to 17 degrees +/- 8 degrees (68% correction, P < 0.001). There were no instrumentation failures, neurologic complications, or infections. The advantages of cobalt chromium alloy wire over steel wire include greater tensile strength and titanium compatibility. Cobalt chromium alloy solid wires may be used as sublaminar implants with titanium spinal instrumentation with excellent clinical results.

Removal of enamel from ultrafine monofilamentary wires

Various techniques for stripping the insulation from very small (e.g., 30 μm diam) single-strand wires (made of copper—as in the case of magnet wire, phosphor bronze, manganin, etc.) without damaging them are discussed. Such approaches include the use of dissolutive chemicals, heat, short-wavelength laser radiation, and rotating friction wheels. A small handheld instrument that employs the last of these methods, and is capable of stripping wires with diameters ranging from 30 to 330 μm, has been developed and is described in detail.

Wireline Integrity Inspection Methods to Prevent Wire Breakage

Abstract The structural integrity and predictable usability of slickline wire has perplexed wireline crews since wireline services were first developed. Miscalculation of wire condition can cause wire failures and costly fishing operations. However, the available alternative-premature replacement of still-usable wire to avoid the first scenario-increases operational costs, especially when the newer corrosion- and embrittlement-resistant nickel and cobalt alloy wires that are commonly used in H2S, CO2, and hot chloride environments are involved. These wires often are ten times as costly as carbon steel and stainless steel alloy wires, and in most cases,. early replacement would not be economically feasible. Until recently, operators have had to rely on experience, "rules of thumb," visual inspection, and destructive tests to determine wire integrity. However, these methods could only provide spot checks; no methods have been capable of accurately assessing the condition of the entire length of spooled wire. This paper will review currently used inspection procedures and a concept that incorporates an existing, non-destructive material inspection technology into a real-time method that can provide the information to determine wire condition over its entire length. Use of this eddy current system can:Evaluate integrity of new wire as it is being spooled onto the reel.Avoid costly replacement of still-usable wire.Facilitate general wire-life assessment.Inspect wire during critical service operations where well environment or operating conditions can cause rapid degradation of the wire. Test results and field operational history are used to illustrate the capabilities and significance of the system. Introduction Slickline is a single-strand wire that can be made of various carbon steel, stainless alloy, and more exotic nickel and cobaltbased alloys and is available in varying lengths and diameters. Slickline lengths are generally between 4,572 to 9,144 m (15,000 and 30,000 ft.), and the most popular outside diameters (OD) are 2.34,2.67,2.74, and 3.18 mm (0.092,0.105,0.108, and 0.125 in.). "Braided line," "mono-conductor," or "multi-conductor" electric wireline consist of braids or multiple strands of smaller-OD wire, which are also available in various carbon steel, stainless and more exotic alloys in varying lengths and diameters. Braidedline and mono-conductor line lengths are generally between 4,572 to 7,620 m (15,000 and 25,000 ft.) with outside diameters of 4.76 or 5.56 mm (3116- or 7h2-in.). Multi-conductor line lengths are generally between 4,572 to 7,620 m (15,000 and 25,000 ft.) with outside diameters of 11.11 or 11.90 mm (7116- or 15h2-in.). Typical Wireline Operation In a wireline operation, tools are attached to the end of a wire and lowered into the wellbore. Once the tools reach their desired depth, they are manipulated in a series of upward and downward motions to perform the desired operation. The wire is stored on a reel in a truck or skid and is generally run through or around a counter wheel and several sheaves (Figure 1). The counter wheel is used to measure the length of the wire deployed into the well.

A Resolution Test Sample for the Scanning Electron Microscope

A test sample that satisfies the restrictive specimen criteria discussed previously for a resolution determination of the SEM is essential. At present, the use of a resolution sample made from a specimen well-known to the particular operator who carries out measurements on the subsequent photomicrograph is the usual procedure. The aluminum-tungsten (Al-W) dendritic structure (located at arrow) in Fig. 1 that remains on the crystal surface of the bead resulting from the melting of aluminum on a hot tungsten filament, provides such a specimen.The dendritic structure found on the Al-W specimen and shown in Fig. 2 is produced by the following technique. A piece of high purity aluminum (99.999%) wire weighing 35 to 40 milligrams is attached to a single coil, approximately 4mm O.D., of a tungsten filament made from 0.5mm (20 mil) single strand wire. The length of the tungsten filament, between the clamped ends of the electrodes in the metal evaporator, is about 6cm.