Ultimate Tension Research Articles

The effects of wind on trap structural and material properties of a sit-and-wait predator

Numerous terrestrial invertebrates use secretions produced by themselves to build prey traps. Potentially, the structural as well as material properties of such constructions will reflect adaptations to wind disturbances, but most relevant studies only focus on trap structural characteristics. In this study, we examined how wind disturbances affected the structural and material properties of prey traps constructed by a sit-and-wait Araneae predator. We first compared web structures and major ampullate (MA) silk properties of 2 Cyclosa spider species inhabiting seashores and forests to see whether these properties reflected the habitat-specific wind disturbances these spiders experienced. The MA silks of the seashore-dwelling Cyclosa mulmeinensis were significantly thicker and contained higher percentage of glycine and lower glutamine. Congruent with such amino acid variation pattern were higher ultimate tension and breaking energy of C. mulmeinensis MA silks. However, despite that this species’ silks were relatively glycine rich and glutamine poor, they also showed greater extensibility. Compared with webs built by Cyclosa ginnaga, those built by C. mulmeinensis were composed of fewer drag-reducing silk threads but were stiffer. In a laboratory manipulation, MA silk amino acid composition and diameter did not differ between C. mulmeinensis receiving different levels of wind. However, those receiving persistent wind disturbances built smaller webs composed of fewer but stronger MA silks to reduce drag and prevent the web from damage. Orb web spiders inhabiting areas with different levels of wind disturbances exhibit variation and plasticity in structural and material properties of prey traps. Furthermore, the silk property plasticity does not have to involve alterations of amino acid composition.

Strength and shrinkage behaviors of roller-compacted concrete with rubber additives

The strength and shrinkage behaviors of roller-compacted concrete (RCR) with used tire-rubber additive were experimentally investigated by keeping the compressive strengths of all specimens at the level of 40 MPa. Four rubber contents were used: 50, 80, 100, and 120 kg/m3. Test results show that the rubber particles homogeneously distributed in RCR, rubber particle emersion was not observed during vibrating for compaction. The workability of RCR was slightly influenced by replacing portion of sand with the same volume of tire rubber particles. RCR specimen exhibited a ductile failure under compression. In comparison with the control concrete, when the compressive strength was kept constant for RCR, the tensile strength, flexural strength, and ultimate tension elongation increased with the increase of rubber content. The incorporation of tire rubber did not help in reducing the drying shrinkage, on the contrary, a little more drying shrinkage developed in RCR than that in the control concrete.

Estimation of ultimate tension load of methylmethacrylate bonded steel rods into concrete

This paper introduces an alternative method of predicting ultimate tension load of methylmethacrylate (MMA) bonded steel rods into concrete. In general, the elastic model is found to predict many of the major experimentally observed characteristics of adhesively bonded steel rods. This theory gives quite reasonable results when applied to epoxy adhesives, but does not agree with data of MMA adhesives. It is necessary, therefore, to modify the analysis in order to bring the elastic model into agreement with test data. This is done by assuming that c, which is a parameter in the analysis, is a function of the shear strain. The solution based on this concept leads to a more general equation which includes as a special case the elastic model previously used to represent the dependence of ultimate tension load on the bond length. Experimental evidence appears to indicate that the ultimate tension load of a MMA bonded steel rod can be predicted, to a good approximation, using this model.

Modified cruciate suture technique for arthroscopic meniscal repair: a technical note

Arthroscopic meniscal repair is the procedure of choice whenever a reparable tear is diagnosed. The cruciate suture for arthroscopic meniscal repair is a type of the outside-in technique. It has advantages like: (1) its ultimate tension load (UTL) is 1.6 times higher than the UTL of the vertical suture (gold standard), (2) it holds the circumferential collagen fibers of the meniscus in a three-dimensional plane compared to the vertical and horizontal sutures which hold the circumferential fibers of the meniscus in a two-dimensional plane, (3) simple instrumentation, (4) could withstand not only distraction forces on the repaired meniscal tear but also, shear forces because of the oblique orientation of the cruciate suture limbs. It has disadvantages like: being difficult to perform and time-consuming. A modified technique is presented in this study which has the following advantages; (1) less time-consuming, (2) performed through a smaller skin incision, (3) a sliding knot is used to tie the cruciate suture.

Optimizing multiple quality characteristics via Taguchi method-based Grey analysis

This paper presents and demonstrates the effectiveness of optimizing multiple quality characteristics of Nd:YAG laser welded titanium alloy plates via Taguchi method-based Grey analysis. The modified algorithm adopted here was successfully used for both detraining the optimum settings of machine parameters and for combining multiple quality characteristics into one integrated numerical value called Grey relational grade or rank. The essential machining parameters were identified as (1) shielding gas, (2) laser energy, (3) traveling speed of the workpiece during welding, (4) focusing position, (5) frequency of the impulse laser, and (6) pulse shape of the primary laser beam. Furthermore, the multiple quality characteristics required herein included: (1) high ultimate tension stress, (2) small heat-affected zone, (3) large welding depth to width ratio, and (4) low surface roughness following laser welding. Titanium alloy plates were butt welded under controlled machine parameter settings, machined, and above quality characteristics were measured. The optimized machine parameter settings clearly improved the quality characteristics of welded plates compared to quality levels achieved for conventional machine parameter settings. The tensile stress increased (922 ± 53 to 965.5 ± 46.5 MPa) and the heat-affected zone decreased (0.27–0.22 mm) while the welding depth to width ratio remained the same at 0.76. The new approach increased the surface roughness from R max of 14.2 to 34.4 μm.

The “Cruciate Suture” for Arthroscopic Meniscal Repair: A New Technique

Meniscal repair has become the treatment of choice whenever a reparable tear is diagnosed. Fixation strength of the repair technique is always of paramount importance in comparison of various techniques, especially after the evolution of many arthroscopic all-inside devices. We present a new arthroscopic meniscal repair suturing technique called “cruciate suture.” One 18-gauge needle and suture material are used. The needle is loaded with the suture material from its tip. The suture is folded at the tip of the needle, which is inserted to penetrate the skin obliquely to appear inside the joint, making a loop. The needle is retracted, while the suture is kept inside of it. The needle is reinserted at the same hole, appearing inside the joint and making a second loop. The needle is retracted completely. With the use of a probe, the loop at the second point is pulled through the loop at the first point, thereby forming a free end. The 2 limbs of the loop are pulled, thus driving the limb with the free end outside of the joint. The first oblique vertical suture is completed at this point. The needle is reloaded by the suture limb from the first point. The previous procedure is repeated, with use of the second skin hole and the third and fourth points to make the second oblique vertical suture. The cruciate suture is now complete. We tested the ultimate tension load (UTL) of the cruciate suture in comparison with that of the vertical suture (the gold standard). A total of 36 tests (18 for the cruciate suture and 18 for the vertical suture) were performed on human menisci. The mean UTL of the cruciate suture was measured at 110 N; the mean UTL of the vertical suture was 67 N.

Prediction of effect of thermo-mechanical parameters on mechanical properties and anisotropy of aluminum alloy AA3004 using artificial neural network

An artificial neural network model, using a back-propagation learning algorithm is utilized, to predict the yield stress, elongation, ultimate tension stress, R ¯ and ∣Δ R∣ during hot rolling, cold rolling and annealing of AA3004 aluminum alloy. Input nodes were chosen as the ratio of initial to final thicknesses, reduction, preheating time and temperature, finish rolling temperature and the final annealing temperature. The maximum error for predicted values was 6.35%, the average of absolute relative error was 0.57% and the RMS was 0.00998. It was found that the mechanical properties and anisotropy of AA3004 alloy sheets can be predicted by this approach.

Simple beam connections in combined shear and tension

An investigation into the behaviour of simple beam-to-column connections subjected to combined shear and tension was carried out by testing 108 full-scale specimens, including header angle, knife angle, single angle, and shear tab configurations. Specimens were rotated 0.03 rad, and a prescribed shear between zero and the design shear resistance was held constant while the specimens were loaded in tension to failure. Results showed significant differences in serviceability, ductility, interactions, and ultimate tension strength. Ductility was provided through yielding in bearing at bolt holes, bending of angle legs, and shear yielding of the gross section of connection elements. Tension and shear load versus displacement plots were acquired for all tests because of ductility and serviceability considerations in design. Existing methods of determining connection resistance, including bolt shear, net section shear, and bearing resistance, were used to compare predicted capacity with test results. The findings of the test program indicate that most simple connections can sustain significant amounts of tension in combination with design shear capacity.Key words: beam, connections, shear, tension, experimental, design, steel.

Optimising multiple qualities of Nd:YAG laser welding onto magnesium alloy via grey relational analysis

This work evaluates multiple quality optimisation of Nd:YAG laser welding onto magnesium alloy via grey relational analysis. The effectiveness of the grey relational grade lies in quantifying and judging the performance obtained using various combinations of laser welding parameters. The parameters are shielding gas, laser energy, travelling speed of workpiece, point at which the laser is focused, pulse frequency, and pulse shape in this work. Moreover, 18 combinations of these six essential welding parameters were set following Taguchi's method to evaluate the integrated performance. The welding parameters that govern the laser beam in thin plate butt welding were evaluated by measuring the ultimate tension stress, and both the depth and the width along the welding path. This integrated performance was then quantified and judged via grey relational analysis to obtain an optimised set-up for laser welding. The verifying test was proved to optimise the ultimate tension stress, depth and width along the welding path from 67·0 MPa, 0·50 mm and 0·77 mm to 142·3 MPa, 0·79 mm and 0·79 mm, respectively.

Liquid Gentamicin in Bone Cement

Liquid gentamicin is approved by the Food and Drug Administration, is readily available, and is much less costly than tobramycin, the more commonly used antibiotic in cement spacers. The purpose of the present study was to test the mechanical properties, elution characteristics, and antibacterial activity of liquid gentamicin in an acrylic bone cement spacer. Standardized specimens consisting of Palacos cement combined with liquid gentamicin, powdered tobramycin, or no antibiotic were fashioned, and the three groups were tested with regard to compressive and tensile strength, elution characteristics (with use of radioimmunoassays), and antibacterial activity (with use of bioassays). The ultimate compression strength decreased by 49% (from 64.65 +/- 3.89 MPa to 32.96 +/- 3.33 MPa) and the ultimate tension strength decreased by 46% (from 35.85 +/- 2.97 MPa to 19.20 +/- 0.36 MPa) when the specimens containing 480 mg of liquid gentamicin were compared with the controls. The addition of tobramycin had no significant effect compared with the controls. The majority of gentamicin was released from the cement during the initial twenty-four hours (mean concentration, 26.4 mcg/mL). The mean concentrations at three and six weeks were 4.15 and 0.65 mcg/mL, respectively. The bioassays confirmed the bactericidal activity of the gentamicin released from the cement. Liquid gentamicin in bone cement is potent and bactericidal. Although the mechanical properties of the cement are significantly diminished by the addition of liquid gentamicin, the temporary nature of the cement spacer makes its use potentially worthwhile given the substantial cost savings to the hospital and the patient.

Tensile fatigue performance of pultruded glass fiber reinforced polymer profiles

Axial tension–tension fatigue experiments were performed on pultruded glass fiber reinforced polymer (GFRP) plates in a laboratory environment. Different full-scale specimen shapes were examined: plate strips as-delivered, plate strips with tabs and plates in tapered form. Experiments were performed up to ten million loading cycles with different frequencies up to 12 Hz. It was observed that the specimen temperature could increase during fatigue test. This increase was dependent on the loading frequency and the loading range. S–N fatigue life curves were determined. Tapered specimens showed a higher fatigue life than as-delivered specimens; and as-delivered specimens showed higher fatigue lives than tabbed specimens. A degradation rate of 3–5% of the single-cycle ultimate tension strength (UTS) per decade of fatigue cycles was observed. This observation is not consistent with a characteristic slope of 10% UTS/decade as shown from many previous studies. A loss of specimen stiffness up to 50% during the fatigue experiments was observed and can only be explained by considerable fiber failures. This finding is consistent with results from previous studies showing that fatigue failure of fiber-reinforced polymer composites is basically fiber dominated. The fatigue behavior of the plates was compared with the fatigue behavior of adhesively bonded double-lap joints made from the same plates. Plates and joints showed converging fatigue life curves and the same fatigue limit at approximately 25% of the single-cycle failure load at ten million cycles.

Optimization of Nd:YAG laser welding onto magnesium alloy via Taguchi analysis

The use of an Nd:YAG laser for thin plate magnesium alloy butt welding was optimized using the Taguchi analytical methodology. The welding parameters governing the laser beam in thin plate butt welding were evaluated by measuring of the ultimate tension stress. The effectiveness of the Taguchi method lies in clarifying the factor that dominates complex interactions in laser welding. The factors can be the shielding gas, laser energy, convey speed of workpiece, point at which the laser is focused, pulse frequency, and pulse shape. Furthermore, 18 combinations of these six essential welding parameters were set and Taguchi's method followed exactly. The optimal result was confirmed with a superior ultimate tension stress of 169 MPa , 2.5 times larger to that from original set for laser welding.

Interleaving methodology for property tailoring of CFRP laminates

The effect of interleaf layers incorporated between laminae on the mechanical properties of quasi-isotropic carbon/epoxy laminates was investigated. Two kinds of laminates, with and without interlayers, were compared in this study. Static and fatigue tests in tension, and vibration damping tests were performed on both laminates. It is shown that introducing the interleaf layers remarkably improved the ultimate tensile load and tension fatigue resistance of the laminates. The interlayers delayed the onset of interlaminar delamination from the free edge and impeded the progression of interlaminar delamination until final failure. It is also shown that the vibration damping of CFRP laminates can be remarkably improved by introducing compliant interlayers between composite plies. The loss factors of interleaved CFRP were 5 through 50 times as large as those for conventional CFRP in the case of quasi-isotropic laminate configuration, which depend upon the location of interlayers between composite plies. Discussion is also made on the optimum interleaf width in the case when the interleaf films were placed only in a limited local area near free edges, in order to tailor the interfacial properties and thus improve the fatigue resistance of quasi-isotropic carbon/epoxy laminates.

Biomechanical investigations of different meniscal repair implants in comparison with horizontal sutures on human meniscus

Purpose: The use of biodegradable implants for arthroscopic repair of meniscal lesions is becoming increasingly popular. The aim of this study was to test the biomechanical stability and the mode of failure of these implants. Type of Study: Biomechanical testing study. Methods: Biomechanical investigations were performed on human menisci using 6 commonly used biodegradable implants for meniscal repair to compare them with horizontal mattress suture using 2/0 Ethibond (Ethicon, Norderstedt, Germany). Included in this study were the Meniscus Arrow (Bionx, Tampere, Finland), Dart (Arthrex, Naples, FL), Stinger (Linvatec, Largo, FL), Meniscal Screw (Innovasive, Marlborough, MA), T-Fix (Acufex, Mansfield, MA), and the Fastener (Mitek, Westwood, MA). The tests were carried out using a material testing machine at a loading rate of 10 N/second. The ultimate tension load (UTL), elongation, and stiffness were evaluated for each implant technique. Results: The highest UTL was shown by Ethibond (62 ± 7.91 N) and the T-Fix (51.35 ± 16.31 N), followed by the Fastener (32.67 ± 2.97 N). All other implants had a significantly lower UTL (P =.001). Less elongation under a load of 5 N was noted for Ethibond (0.64 ± 0.25 mm) and for T-Fix (0.43 ± 0.32 mm) compared with the other implants. The greatest elongation was found for the Fastener (2.239 ± 0.581 mm). The stiffness of the fixation was similar in all implants, except for the Dart and Fastener, which were significantly inferior (P <.05). Conclusions: All of the biodegradable implants had lower UTL than the suture techniques. Therefore, when using the implants, they should be inserted close together to provide sufficient stability. In cases of an extended lesion, there might even be an option to combine the implant and suturing techniques.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 5 (May-June), 2001: pp 439–444

Parametric study of factors affecting the pull-out strength of steel rods bonded into precast concrete panels

This paper deals with the effect of bond thickness, embedment length and type of epoxy adhesive formulation on the adhesion of steel anchors to concrete. The test results indicate that the shear strength of the epoxy adhesive formulation prepared from a diglycidylether of bisphenol A (DGEBA) and an ethyleneamine curing agent is independent of bond thickness from approximately 1–4 mm. However, the same is not found to be true for the DGEBA epoxy resin cured using an alkylenediamine curing agent where considerably more complex behaviour is observed. The adhesive shear strength of this system is shown to pass through a maximum value at 2 mm bond thickness. At thickness beyond 2 mm, the strength undergoes a reduction until a value is reached which remains essentially constant with increased thickness. The variation in concrete strength is regarded as a main factor responsible for this complexity. The addition of filler to epoxy adhesive formulations results in a reduction in the adhesive shear strength, the magnitude of the decline being largely dependent upon the quantity of filler used in the mixture. The quadratic equations reviewed in this study provide a basis for assessing trends in the mechanical behaviour of filled epoxy systems. The shear strength of an epoxy adhesive anchor can be determined by an elastic behavioural model. The curves for epoxy adhesives indicate that the elastic solution does fit the experimental data very well. Increasing embedment of an anchor beyond a certain point does not increase the ultimate tension capacity of the anchor.

Mechanische Eigenschaften von Fadenmaterialien zur Verankerung von Kreuzbandtransplantaten

The fixation of hamstring grafts in ACL reconstruction requires a connector device. During the process of ingrowing the graft stability depends entirely on the fixation. The following study focused on the mechanical conditions of no 6 Ethibond, 5 mm Mersilene tape and 5 mm Polylene tape. The material were tested as loops with a length of 30 mm including the knot similar to intraoperative conditions. The ultimate tension load and elongation of the conditioned and unconditioned loops were investigated under cyclic load of 50 N and 100 N using a tension load machine. The ultimate tension load increased significantly only for Mersilene from 416 N to 462 N. However, the highest ultimate tension load showed Polylene with 479 N. The oscillating load up to 100 N revealed for unconditioned loops an elongation of 4.1 mm for Ethibond, 2.9 mm for Polylene and 5.4 mm for Mersilene. The elongation decreased significantly for the conditioned loops to a maximum of 1.4 mm. Concerning the amplitude during the period of oscillating load there was found a significant reduction as well. Based on our results Polylene showed the best mechanical properties. Regardless the intraoperatively used material we advocate the conditioning of the loops before anchoring the hamstring graft in ACL reconstruction.

Reduction of Tensile Strength in Angle-Ply Composite Laminates Due to Low-Velocity Impact

The purpose of the present paper is to evaluate the tensile strength reduction of angle-ply composite laminates due to low-velocity impact. Three angle ply lay-up were chosen: [+30',-300]2s, [+45',-45oI2s and +60',[-60]2s. Impact tests were performed at different impact energy level and then an ultrasonic scan NDI was performed, to evaluate the internal damage. The impacted specimens were subjected to tensile load until failure occurs and the ultimate tension strength after impact was compared with the corresponding value for undamaged specimens. Moreover, for a better understanding of the failure phenomenon, some tension tests for damaged specimens were interrupted at different load levels (respectively at 30%, 60%, 85% and 90% of the corresponding failure load) and ultrasonic scans at any step were performed to evaluate the delamination growth due to tensile load. A correlation between the amount of delamination areas and the impact energy has been determined.

Simple beam connections in combined shear and tension

An investigation into the behaviour of simple beam-to-column connections subjected to combined shear and tension was carried out by testing 108 full-scale specimens, including header angle, knife angle, single angle, and shear tab configurations. Specimens were rotated 0.03 rad, and a prescribed shear between zero and the design shear resistance was held constant while the specimens were loaded in tension to failure. Results showed significant differences in serviceability, ductility, interactions, and ultimate tension strength. Ductility was provided through yielding in bearing at bolt holes, bending of angle legs, and shear yielding of the gross section of connection elements. Tension and shear load versus displacement plots were acquired for all tests because of ductility and serviceability considerations in design. Existing methods of determining connection resistance, including bolt shear, net section shear, and bearing resistance, were used to compare predicted capacity with test results. The findin...

Axial Decay of Self-Equilibrating End Loads in Compressible Solids

The axial diffusion rate of self-equilibrating surface loads is investigated for axially prestretched solids under plane-strain conditions. The perturbed field within the body, induced by an instantaneous end disturbance, is examined by using the eigenfunction spectral analysis. A general solution is given for a wide range of compressible materials. Particular examples are presented for a few hyperelastic solids. Very slow rate of decay, of the first antisymmetric eigencomponent, has been found near the stress-free configuration. Also, there is almost no decay of the first symmetric eigencomponent near the ultimate tension load. The diffusion length is greater for less compressible solids. Axial decay is exponential and depends quite strongly on material moduli and prestrain.

An Application of Failure Theory to Burley Tobacco Stalk

The Hencky-von Mises theory of failure was developed for an orthotropic material with loads in tension perpendicular to the grain and in shear parallel to the grain with the objective of determining the application to the failure of woody plant materials represented by the burley tobacco stalk. When the tension and shear components are calculated by dividing the tension shear stresses by the ultimate tension and shear strengths, respectively, the Hencky-von Mises model indicates that the sum of the square of the tension and shear components should equal 1.00. Combined states of stress were induced in the burley tobacco stalk and the loads increased until failure resulted. The average experimental value of 0.78 was compared to the theoretical value of 1.00 via T-test which showed the two values to be significantly different at the 1% level. Therefore, our results failed to verify the applicability of the Hencky-von Mises theory to the failure of burley tobacco stalks.