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Copyright of International Journal of Production Research is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Production Research is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

When machining was carried out in precisely defined conditions, the derived strain at the borderline between continuity and discontinuity in machining was found to be similar in magnitude to that of the strain as determined by a torsional test for a variety of metals which individually exhibit very different magnitudes of shear strain at failure. The effect of compressive stress on the extension of shear strain to fracture during machining was found to be similar to the effect on shear strain observed during a conventional torsional test when compressive stress was added. The effect of rake angle and feed rate on the change from continuous to discontinuous chip formation was correlated with the shear strain and evaluated normal compression on the primary shear plane, when the lateral spread of the deformed chip was constrained. [ABSTRACT FROM AUTHOR]

The scope of the current research on sheet metal forming is surveyed in the light of precise definitions of stretchability on the one hand, and deep drawability on the other. Particular emphasis is placed on the elucidation of basic concepts brought about by recent research, such as the distinction between the ductility of the material and the extent to which it is exploited in a particular process. Several outstanding problems in sheet metal forming are discussed for their potential benefit to sheet metal engineering. It is believed that present results will lead to greater refinement in the specification and selection of sheet metal in the future, as well as to investigations on such problems as wrinkling and non-coaxial strain paths. [ABSTRACT FROM AUTHOR]

The following analysis determines the direction of the chip flow in free oblique cutting, based on the fact that the friction force on the tool face takes the direction of the relative motion of the chip along this face. This direction is shown to be one of minimum deviation of the material as it shears.
The condition of minimum work yields a general expression for the shear angle. The dimensions of the chip section and the cutting forces are predicted by theory. An energy balance for oblique cutting is made. This general solution yields the well-known solutions of Merchant's model for orthogonal cutting as an obvious special ease. [ABSTRACT FROM AUTHOR]

The theory of wire drawing is modified to allow calculation of a hydrodynamic film thickness and viscous friction coefficient using Reynold's equation for the lubricant. Two cases, viz. (i) constant film thickness, (ii) exponential variation in film thickness, have been studied. The film thickness is determined by the principle of minimum rate of entropy production. It is shown that the apparent coefficient of friction varies significantly within the die. At small reductions there is an optimum die angle and under certain conditions there may be no optimum die angle. With the increase in speed (beyond some critical value) the drawing stress reduces. [ABSTRACT FROM AUTHOR]

This paper is concerned with the evaluation of tool stresses in the orthogonal cutting process. Theory and elasticity methods are applied to determine these stresses within the elastic region. In this analysis the tool is considered as a wedge with the normal and frictional loading on the rake face. For general conditions of loading it has been found that the equivalent stresses are of the order of a hundred thousand pounds per square inch. It has also been found that tine equivalent stresses decrease with positive rake and increase with negative rake. [ABSTRACT FROM AUTHOR]

In this paper the Filon's transformed equations have been applied successfully to evaluate the chip-toot interface stresses of a cutting tool from the photo-elastic data. This method is shown to be advantageous over the shear difference method, particularly for negative rake tools. The analysis was carried out to study the effect of rake angle and depth of cut on the stress distribution and total forces on the rake face, involved in the orthogonal machining process. [ABSTRACT FROM AUTHOR]

The paper shows how the governing equations are modified by allowing a variation in yield stress throughout a deformation zone. The limitations imposed by these equations are discussed and a method is proposed to illustrate the effect of variable yield stress on the deformation pattern. From the study of a particular solution of plane strain extrusion, it is concluded that variation in yield stress should not markedly change the pattern of deformation from that appropriate to a non-hardening situation. This conclusion, therefore, gives support for the mean strain solution currently employed to accommodate strain hardening, particularly if this method is applied incrementally along the streamlines. [ABSTRACT FROM AUTHOR]

Calculations are made of the strains and final dimensions of an initially flat blank formed by a rubber punch over a rigid die having two principal radii of curvature. Both stretch and shrink flanging are considered. [ABSTRACT FROM AUTHOR]

A hammer having a face in the shape of a thin rectangle is assumed to produce a plane-strain indentation. By applying rings of blows to a thin disc with the hammer face oriented circumferentially or radially, various axi-symmetric distributions of internal stress may be set up. Theoretical stresses were used for calculating changes in stiffness in various harmonic modes of flexure. Hence, effects of distributions of the two types of blow were assessed. The theoretical results, confirmed by controlled experiments, serve to elucidate some aspects of workshop practice. [ABSTRACT FROM AUTHOR]

A method is proposed which provides the force for a given axi-symmetric plastic deformation process. The method is based on equilibrium considerations of the stress system arising from a kinematically admissible system of velocity discontinuities. The circumferential stress is defined by the Haar and von Karman assumption. This assumed pattern of velocity discontinuities is adjusted to give a minimum value of applied force. The method is considered in the context of the extrusion process and is shown to agree with an alternative upper bound solution, both solutions being in reasonable agreement with experimental results. By a comprehensive evaluation of the extrusion loads for various reductions, frictional conditions and cone angles, the method may be used to predict the formation of dead zones. Experimental results for the extrusion through lubricated 90' dies show reasonable agreement with such predictions. [ABSTRACT FROM AUTHOR]

Strips of various metals were compressed statically and dynamically to produce plane-strain deformation. The dies used had flat faces of various widths in relation to strip thickness. Attention was given chiefly to the amount of bending of the strip relative to the amount of stretching. Results could be compared with values calculated for a rigid-plastic material, though an initial elastic-plastic phase of deformation was usually evident. The amount of bending produced by impact loading was found to be limited by inertia of the strip. [ABSTRACT FROM AUTHOR]

The deformation of grids scribed on the workpiece surface after passage of the material into the chip may be studied in association with the predictions of some appropriate theory. Such a theory based on the assumption that the workpiece material is deformed solely by simple shear is developed in this paper.
The distribution of plastic strains in the metal-cutting process has generally been studied by measuring the distortion of a grid scribed on the surface of the uncut material. Christopherson, Oxley & Palmer (1958), Okushima & Hitomi (1959), Rosenberg & Kufarev (1958), and Russell & Brown (1964) have used this method. In certain cases the distribution of strains is difficult to determine by this means and other methods must be employed. Such cases arise when either the depth of cut or the size of the deformation region is small in relation to the smallest size of grid unit which may be conveniently ruled or deposited on the surface.
In this paper, the preliminary assumption is made that an elementary square grid unit is deformed solely by simple shear into an elementary parallelogram and that, as a result, the shape of the element remains either that of a parallelogram or a rectangle throughout its passage into the chip. [ABSTRACT FROM AUTHOR]

In recent experiments on blanking and piercing it was found that cracks occurred in the region of maximum hardness gradient and that cracking could be eliminated by reducing the punch and die edges. In this paper a simple stress analysis is made of the corresponding plane strain deformation, account being taken of the strain-hardening property of the work material. The above experimental observations are then shown to be compatible with the predicted stress distributions. [ABSTRACT FROM AUTHOR]

An experimental technique had been developed for studying cutting with single tools of known geometry at very small depths of cut. It has been shown that the specific cutting energy decreases as the thickness of the cut is decreased, a result which is contrary to that obtained in previous investigations with grinding wheels and to that expected from consideration of the influence of specimen size on the yield value of shear stress. These apparent anomalies are discussed in terms of the width of cut and the size of the plastic zone. [ABSTRACT FROM AUTHOR]

A unique milling cutter dynamometer has been designed and developed which enables radial and tangential forces acting on a cutter tooth to be recorded throughout its cutting action. The research value of this instrument has been demonstrated in a series of comparative experiments involving up-cut and down-cut milling. This paper is based on original research reports of the design (Smith, 1958) and development (Ever, 1959) of a milling cutter dynamometer. Hitherto, the measurement of forces in peripheral milling has been mainly by dynamometer mounted on the machine table, though a few have analysed the torque and vertical force on the arbor. In such cases, standard cutters are used and the total vertical, horizontal or axial force is obtained. This present dynamometer has been designed to make possible direct measurement of the radial and tangential forces acting on a cutter tooth, throughout the formation of a single chip. A diagram of the dynamometer is given in Figure 1. The cutting tooth is carried in a block (1), the opposite end of which slides in the main body. Tangential movement of the cutter is restrained by straps (2) on either side of the body, and radial movement is restrained by strap (3) within the body. Strain, under load, of these straps is picked up by the perspex strain rings (4) and (5) each of which carries four resistance strain gauges forming a bridge unit. [ABSTRACT FROM AUTHOR]

A stress-strength model is formulated for s of k systems consisting of identical components, We consider minimum variance unbiased estimation of system reliability for data consisting of a random sample from the stress distribution and one from the strength distribution when the two distributions are exponential with unknown scale parameters, The asymptotic distribution is obtained by expanding the unbiased estimate about the maximum likelihood value and establishing their equivalence. Performance of the two estimates for moderate samples is studied by Monte Carlo simulation. Uniformly most accurate unbiased confidence intervals are also obtained for system reliability. [ABSTRACT FROM AUTHOR]

The article presents a simplified version of the Owen-Grosberg flexural-rigidity tester with improved sensitivity. The flexural rigidity of a material is defined as the ratio of the bending mechanism produced. Several tests were conducted through very small test pieces. The solution for finding a crease-free sample is solved. The testing instrument Drayton motor with an automatic reversing switch is also utilized as a testing method. A horizontal force is applied to the lower end of the pointer to keep it vertical.

The results of previous work on the bending-strain levels and frictional components of fabric-bending are used to predict fabric-bending recovery from published data on fibre-bending recovery. Good agreement is found between predicted and experimental results. [ABSTRACT FROM AUTHOR]

Experiments are described in which the extensional, bending, and twisting strains of seven fibres were measured in a wool worsted fabric deformed in a multiple-pleat tester. The only significant strain appeared to be the bending strain. [ABSTRACT FROM AUTHOR]

A new equation is proposed for the description of the static creep of dental amalgam. It is satisfactory for a wide range of stresses and strain rates in static creep experiments during steady state. The hypothesis was confirmed that creep of dental amalgam is determined by the low melting phases. [ABSTRACT FROM AUTHOR]

The moiré fringe technique of strain analysis was applied to small beams of resin restorative materials. The feasibility of using this technique on small dental materials specimens was established. [ABSTRACT FROM AUTHOR]

This report describes an investigation by means of laboratory tests of the critical shear stress and bed erosion as a function of time and bed shear stress for a sediment consisting of alternating sand clay layers 0.1-3cm thick (sand-clay laminae). This type of deposit occurs quite frequency in estuaries and tidal inlets. The tests were carried out on an original bed deposited in an estuary. The critical shear stress and the degree of relation to time for the sand-clay lamination were found to agree in order of magnitude with those for clay layers. The resistance to erosion of the sand-clay lamination ids therefore comparable with that of clay layers. [ABSTRACT FROM AUTHOR]

An investigation is described in which bending stress-strain curves of several keratin and synthetic fibres were obtained up to bending strains as high as 20%. These results suggest that low-stress compressive yielding is occurring at the intrados of the synthetic fibres during bending. The keratin fibres, on the other hand, do not appear to yield in compression, if at all, until much higher stresses are reached. The variations in nominal bending moduli of wool, nylon, and Terylene fibres with changes in temperature and relative humidity were also investigated. [ABSTRACT FROM AUTHOR]

A study of the migration of fibres in open-end-spun yarns is reported. Samples of viscose rayon yarns were produced by the drum and air-vortex methods, and the results obtained on them were compared with those for a ring-spun yarn made from the same fibre. Migration was studied by determining three parameters: the helix profile, the mean fibre position, and the r.m.s. deviation, i.e., the root-mean-square value of the radial deviation of the helix profile from the mean fibre position. The geometry of fibre-packing in the yarn cross-section and the fibre extent were also studied. It is shown that open-end-spun yarns are somewhat different in character from ring-spun yarns and that the most basic structural differences are found in the fibre extent, fibre migration, and fibre-packing density. The fibre migration in an open-end-spun yarn is shown to be as little as one-sixth of that in a typical ring-spun yam, and the difference in structure is important in that it can affect the yarn properties. It is concluded that the observed low strength of most open-end-spun yarns can be attributed to the poor fibre extent and inferior fibre migration within the yam body and that their relatively high elongation can be explained in terms of the folded and entangled nature of the fibres. An examination of the fibre geometry in the yarn shows that the design features of drum spinners are important with regard to the determination of the fibre extent, a tangential feed being preferable to an axial one. The yarn cross-sections demonstrate that open-end spun yarns generally have a lower fibre-packing density than ring-spun yams, which tends to give the yarn a more bulky nature; this is consistent with what might be expected from an assembly of tangled fibres. [ABSTRACT FROM AUTHOR]

An account is given of an experimental investigation of the normal snarling of highly twisted monofilaments, those used being vulcanized rubber and nylon. An earlier theoretical analysis is corrected, and the experimental results show that, after this correction, the theory put forward for the mechanical properties of the snarling mechanism holds reasonably well for elastic filaments. Although, as would be expected, there are larger deviations from the theory for visccelastic filaments, the theory still gives a good indication of the behaviour of these filaments under torsion. [ABSTRACT FROM AUTHOR]

An account is given of an experimental investigation of the cylindrical snarling of highly twisted monofilaments. The theory underlying cylindrical snarling is set out, and an expression is derived for calculating the critical twist level at which normal snarling will be replaced by cylindrical snarling. Experiments on rubber filaments are described, and it is shown that there is good agreement between the theoretical and experimental results. Further experiments, in which the specimen was allowed to contract freely or forced into other forms, are also described. It is shown from these experiments that it is difficult to establish the true equilibrium behaviour, since the situation appears to be dominated by frictional effects or by direct barriers to relative movement. [ABSTRACT FROM AUTHOR]

Certain aspects of the handle of fabric laminates are related to properties of the component fabrics. Particular attention is paid to a theoretical prediction of the bending stiffness of a laminate from the bending and tensile properties of its components. This theoretical stiffness is a minimum value; if, in practice, the observed stiffness is much greater than this, it may generally be assumed that excess of adhesive or of melted foam is the cause. The paper also reports work on other features of the bending behaviour, such as the degree of recovery from bending, and on the shearing behaviour. The work is concluded by a brief study of some faulty laminates. [ABSTRACT FROM AUTHOR]

The simultaneous stabilization of set and shrink proofing of pre-chlorinated wool fabric can be achieved by the condensation of a di-isocyanate with a polyamine or a polyalcohol across the wool-liquid-phase boundary. When polymerization occurred at the interface between two immiscible solvents, a high degree of shrinkage-resistance, but no set-stabilization, was obtained. Polymers derived from the reaction of a polyamine with diacid chlorides or bis(chloroformates) failed to stabilize the set and produced satisfactory shrink-resistance only when formed by condensation at a liquid-liquid interface. Polymers derived from the reaction of a polyamine with divinyl sulphone, epichlorohydrin, or formaldehyde failed to shrink proof the wool and lowered the set stability produced by the action of divinyl sulphone, epichlorohydrin, or formaldehyde alone. The mechanism of set-stabilization by polymers is discussed in terms of fibre-encapsulation and inter-fibre bonding. [ABSTRACT FROM AUTHOR]

Previous papers have described the use of the cloth-bending-hysteresis test in investigating the detailed bending behaviour of fabrics. An account is given in this paper of the use of the techniques of regression analysis to investigate the correlation between the results of this test and other mechanical tests with subjective assessments of cloth stiffness and liveliness for two groups of fabrics. The correlations are shown to be highly significant, and good estimates of these two subjective properties could be made from the laboratory tests. [ABSTRACT FROM AUTHOR]

Shrinkproofed, set wool can be given a permanent-press finish by treatments that prevent molecular rearrangements during laundering. The stabilizing reactions must not occur until after adequate disulphide-bond rearrangement and stress relaxation have been brought about during setting. Of the various types of set-stabilizing treatment examined, cross-linking, when applied prematurely, had the greatest inhibiting effect on subsequent setting, even when the fabric was in the required configuration during cross-linking. Cross-linking alone in the required configuration does not confer adequate set or stability to laundering. [ABSTRACT FROM AUTHOR]

The stress-strain behaviour (at constant rate of extension) for fibres at 0, 65, and 100% r.h. is compared. At 100% r.h., the material yield slope is close to zero, whereas a rapid stress relaxation at 65 % r.h. leads to a negative slope. This latter effect tends to be masked by fibre non-uniformity. The fibre-material yield slope at 0% r.h. is quite large, and the slow turnover from Hookean to yield is probably an interaction between this slope and fibre non-uniformity. Constant-rate-of-loading tests by others do not indicate a negative slope at 65% r.h., and the material yield slope at 0% r.h. appears to be significantly higher for this mode of testing. The variation in the stress at 15% extension in water from fibre to fibre appears to be mainly due to microfibril-proportion differences existing between fibres. A similar effect for the Hookean slope in water tends to be complicated by additional crimp effects. The post-yield-region variation decreases for lower humidities, and an explanation in terms of the series-zone model is suggested. Fibre non-uniformity greatly affects the observed breaking properties, and the actual material breaking properties are derived from the results. [ABSTRACT FROM AUTHOR]

A brief summary of certain phenomena associated with the two stages of supercontraction in aqueous lithium bromide solution is given; in particular, the mechanical properties, in the cold solution, of wool fibres at the end of each stage are discussed. Results previously obtained by Feughelman and Haly are reinterpreted in terms of the simple two-phase model of crystalline microfibril embedded in a less ordered matrix. On the basis of certain assumptions, it is possible to obtain an estimate of the stress-strain curve of the matrix in LiBr solution. The matrix stress-strain curve so obtained compares well with the theoretical inverse Langevin rubber-elasticity curve up to a certain strain level. A value for the number of random links between cross-links is obtained. [ABSTRACT FROM AUTHOR]

An account is given of an investigation of the effectiveness of steaming on the longitudinal stabilization of wool yarn. Specially prepared worsted yarns were used to study the effects of initial regain and of time and temperature of steaming. Of the several different mechanisms proposed for the longitudinal stabilization of yarn by steaming, only permanent setting is demonstrated directly, and the effects of temperature, initial regain, and time of treatment are established. Two threshold values were observed below which no permanent setting took place—an Initial-regain threshold of 7-8 % and a temperature threshold of about 88 °C. It is considered possible that the threshold temperature is a function of the particular release treatment used and that it would increase with increasing severity of the conditions of release. The contribution of permanent setting to the over-all longitudinal stabilization was apparently small, but this may have been a result of using a rather severe release treatment. [ABSTRACT FROM AUTHOR]

study of the changes in mechanical properties of cotton brought about by sodium hydroxide, an iron tartrate complex in caustic soda (EWNN), cuprammonium hydroxide, and sulphuric, phosphoric, nitric, and perchloric acids has been made. Instead of choosing the normal mercerizing conditions with sodium hydroxide, different temperatures of treatment and of washing were studied to see what effect the condition had on the subsequent mechanical properties of the fibres. The variable studied with the other reagents was that of concentration, so that a distinction between interfibrillar and intrafibrillar swelling could be made. The main effect of swelling is to alter the extensibility of the fibre, and this has been analysed at different stages of loading up to break. [ABSTRACT FROM AUTHOR]

An account is given of a study of the extent to which fibres were pulled through the web during needling that was made by incorporating one layer of coloured fibres at various positions in a 50-layer web. The number of needle locations at which tracer fibres appeared and the number and length of fibres were determined. Further studies of the occurrence of interlocking loops on the surface of a needled fabric are reported. [ABSTRACT FROM AUTHOR]

Cotton fabric has been methylated under a variety of conditions. The extent of methylation has been shown to be dependent on the time of methylation and on the degree of swelling or disruption of structure. The latter is caused by the alkali pretreatment or by the swelling of the partly methylated cellulose. Fabric physical properties have been measured and the influence of the methylation treatment has been examined. [ABSTRACT FROM AUTHOR]

A new type of yarn structure, which has been named self-twist yarn, is described. It is a two-ply structure in which both the strand and plying twists alternate S and Z along the yam. The strength properties of the yarn and their dependence on the various yam parameters are given for 60/64s wool fibres, and it is shown that the strength can approach that of conventional yarns. [ABSTRACT FROM AUTHOR]

Stress-strain data for wool fibres of different origin are presented, the tests having been made under different moisture conditions. Small differences exist between wool fibres from primary and secondary follicles from the same animal, the secondary being easier to stretch both initially and finally under wet conditions. However, the relative yield slope is markedly higher for secondary than for primary fibres. Differences exist between and within breeds in the initial modulus, the stress at 15% extension, and the slopes of the curves in the yield and post-yield regions. [ABSTRACT FROM AUTHOR]

The relevance of the extensional recovery of single filaments to the resilience of textiles is discussed, and tests are described that yield information at three different effective rates of loading. The methods considered are: (i) cyclic measurements on an Instron Tensile Tester; (ii) recovery from a sustained extension; and (iii) recovery from impact. Applications of these methods will be discussed in two later papers. [ABSTRACT FROM AUTHOR]

A brief summary of the structure of keratin fibres is followed by a review of their mechanical and allied properties. Among these properties are tensile stress-strain properties, stress relaxation, and creep, and torsional stress-strain properties and stress relaxation. The mechanism of supercontraction, properties of set fibres and disulphide-reduced fibres, and thermal transitions in keratin are also discussed. Finally, the various theoretical attempts that have been made to explain these properties are critically reviewed. [ABSTRACT FROM AUTHOR]

Various theories of fibre structure are briefly reviewed, and it is shown that the original ‘fringed-micelles’ theory is no longer considered valid. The influence of the genesis of fibres on their structure is demonstrated, and it is shown that, because of this difference in fibre formation, it is difficult to fit a single model to all fibres. The architectural models proposed for various fibres are discussed, and it is pointed out that the validity of these models can be tested by reference to the fibre properties. It is emphasized that there is still insufficient knowledge of the behaviour of fibres subjected to transverse stresses, and it is shown that some of the phenomena that occur under the action of such stresses can be explained by the comparatively recent ‘fringed-fibrils’ theory of fibre structure. Finally, attention is drawn to some aspects of the structure and behaviour of fibres that are still unexplained, and towards which it is proposed that further research should be directed. [ABSTRACT FROM AUTHOR]

This paper describes a detailed theoretical and experimental investigation into the relationship between wool-fibre non-uniformities and stress-strain behaviour. The shape of the stress-strain curve in the yield region is closely related to the fibre cumulative cross-sectional-area distribution. The fibre-material yield slope is found to be nearly zero, and the changes from Hookean to yield region and from yield to post-yield region for the material are quite sharp. The observed relative yield slope (relative to the stress at 15% extension) and the coefficient of variation of area interact in the manner predicted except that there are quantitative differences between the experimentally and theoretically derived relationships; these deviations are interpreted as structural effects due to fluctuations in the stress at 15% extension along the fibres, a variation that is relatively independent of the changes in cross-sectional area along the fibres. The mean effective coefficient of variation of area due to this structural variation is found to be of the same magnitude as the mean coefficient of variation of area for the wool-fibre types examined. Previous results relating crimp to the cross-sectional area and the Hookean slope are confirmed; within the fibre groups, thicker fibres have a higher crimp level and a lower relative Hookean slope (relative to the stress at 15% extension), whereas between groups the thicker fibres have a lower crimp level and a higher relative Hookean slope than thinner fibres. The stress at 15% extension is significantly different for the different wool-fibre types, which indicates real structural differences between the fibre types. As the fibre mean cross-sectional area increases, the fibres show a tendency to be structurally ‘stronger’, the magnitude of this effect agreeing with values obtained by other investigators. Thinner fibres, as well as being structurally ‘weaker’, tend to be more variable in cross-sectional area and less elliptical in cross-section. [ABSTRACT FROM AUTHOR]