Determination of screw pull out forces from screw thread channels

2021 ◽  
Keyword(s):  
Screw Thread ◽  
Pull Out

Methods for Determination of Rubber to Cord Bond Strength

1959 ◽  
Vol 32 (3) ◽  
pp. 898-906
Author(s):  
R. V. Uzina ◽  
L. S. Gromova ◽  
S. A. Vasil'eva
Keyword(s):  
Bond Strength ◽  
Laboratory Method ◽  
Single Thread ◽  
Vulcanized Rubber ◽  
Pull Out ◽  
Cord Fabric ◽  
Fabric Structures

Abstract In selecting methods for determination of rubber to cord bond strength it is necessary to consider the factors which are subject to variation in the system— the type of cord, the composition of the vulcanized rubber, or the composition of the impregnant. The selection (composition) of the methods of assessment of bond strength was carried out in the present study while keeping the type of cord and the rubber compositions constant ; only the composition of the impregnant was varied. Up to the present there has been no single laboratory method for evaluating rubber to cord bond strength for the determination of the service quality of rubber-fabric structures. The bond strength in such a system is assessed in the majority of cases by the use of a series of methods. The existing methods may be systematized according to the nature of the deformation (static or dynamic), the nature of the specimen (with single thread of cord or with cord fabric) and so on. We adopted the following classification of methods: 1). Determination of bond strength of a single thread of cord with the rubber; 2). Determination of bond strength of rubber to fabric model specimens. Determination of bond strength of a single thread of cord with rubber is an exceptionally widely used type of testing in the rubber industry. It is based either on the principle of stripping of a single thread of cord from the rubber under pressure, or on the principle of pull-out of a thread of cord from a rubber specimen.

Effect of Interfaces on Fiber Fracture in Mg and MgLi Matrix Composites

2005 ◽  
Vol 482 ◽  
pp. 355-358 ◽  
Author(s):  
S. Kúdela ◽  
H. Wendrock ◽  
L. Ptáček ◽  
S. Menzel ◽  
K. Wetzig
Keyword(s):  
Ex Situ ◽  
Matrix Composites ◽  
Interfacial Bond ◽  
Fiber Fracture ◽  
Composite Failure ◽  
Pull Out ◽  
Fiber Fragmentation ◽  
Scanning Electron

Fibers fracture in tensile strained Mg and MgLi matrix composites strengthened with ~10% vol. short δ-Al2O3 fibers (Saffil) is investigated by „in-situ“ scanning electron microscopy and ex-situ“ determination of the length of fibers chemically recovered from tensile failed composites. Little interfacial reaction in Mg matrix composite results in poor interfacial bond so that composite failure proceeds via fiber pull-out with negligible fiber fragmentation. On the other hand, extensive fiber/matrix reaction in MgLi matrix composites promotes formation of strong interfaces which are linked with multiple fiber cross-breakage during tensile straining. These results are consistent with experimental tensile strengths of related composites.

scholarly journals A new current weigher, and a determination of the electromotive force of the normal weston cadmium cell

1907 ◽  
Vol 80 (535) ◽  
pp. 12-18
Keyword(s):  
Current Sheet ◽  
Electromotive Force ◽  
Unit Length ◽  
Screw Thread ◽  
Late Professor ◽  
Convenient Formula ◽  
Association Meeting ◽  
Helical Current ◽  
Mutual Induction

The instrument described is the outcome of conversations between the late Professor J. Viriamu Jones, F. R. S., and one of the authors (W. E. A.), on their return from the British Association Meeting held in Toronto in 1897. Its object was to determine “ the ampere ” as defined in the C. G. S. system, to an accuracy comparable with that attained in the absolute determination of the ohm by Lorenz’s apparatus, an account of which was given by Professors Ayrton and Jones at the Toronto Meeting. Professor Jones had previously developed a convenient formula for calculating the electromagnetic force between a helical current and a coaxial current sheet, viz., F = γ h γ (M 2 -M 1 ),† where γ h is the current in the helix, the γ current per unit length of the current sheet, and M 1 , M 2 the coefficients of mutual induction of the helix and the two ends of the current sheet respectively. By using coaxial coils with single layers of wire wound in screw-thread grooves, advantage could be taken of the above formula.

scholarly journals Influence of pedicle screw thread width and recovery time after surgery on fixation strength

2021 ◽  
Vol 7 (2) ◽  
pp. 751-754
Author(s):  
Harikrishna Makaram ◽  
Ramakrishnan Swaminathan
Keyword(s):  
Cortical Bone ◽  
Pedicle Screw ◽  
Stress Shielding ◽  
Stress Transfer ◽  
Fixation Strength ◽  
Screw Thread ◽  
Fe Model ◽  
Contact Conditions ◽  
Transfer Parameter ◽  
Pull Out

Abstract Introduction: Pedicle screw fixation systems are widely used for treatment of various spinal pathologies, including spinal stenosis, scoliosis, spinal deformities and fractures. Stress shielding is considered to be a major factor contributing to insufficient fixation strength, leading to screw loosening. In this study, the influence of pedicle screw thread width on the displacement of pedicle screw and stress transfer is analyzed using 2-Dimensional axisymmetric finite element (FE) model. Methods: FE model consisting of cancellous and cortical bone, along with pedicle screw is developed for this study. The pedicle screw thread width is varied between 0.1 mm and 0.6 mm in steps of 0.1 mm, while the other geometric parameters, including screw half-angle, pitch, diameter, and length are kept constant. Three different contact conditions between screw and bone, such as frictionless, frictional, and bonded are considered to simulate hours, days, and months after surgery, respectively. The material properties and boundary conditions are applied based on previous studies. An axial force of 80 N is applied on the screw head to simulate axial pull-out test. Results: Similar patterns of stress distribution are observed for all screw models, with high stress concentration above the first thread. The highest displacement in screw is observed shortly after surgery, while the highest displacement in cancellous and cortical bone is observed few days and months after the surgery, respectively. The average von Mises stress in screw decreases with increase in thread width for all contact conditions. In few hours/days after the surgery, stress transfer parameter increases with increase in thread width, up to a thread width of 0.5 mm and then decreases. The changes in stress transfer parameter are negligible few months after the surgery. Conclusion: This study highlights the influence of thread width on displacement and stress transferred to the bone, at different durations after the surgery. It is observed that a thread width of 0.5 mm exhibits the highest stress transfer, leading to reduced stress shielding and improved bone remodeling. It appears that this study might aid in developing better pedicle screws for the treatment of various spinal pathologies.

Determination of the Bond Strength of Wood Veneer and Geopolymer Matrix by Means of a Pull-Out Test

2020 ◽  
Vol 981 ◽  
pp. 162-168
Author(s):  
Siti Noorbaini Sarmin ◽  
Wan Mohd Nazri Wan Abdul Rahman ◽  
Nor Yuziah Mohd Yunus ◽  
Nurrohana Ahmad
Keyword(s):  
Picea Abies ◽  
Moisture Content ◽  
Bonding Strength ◽  
Treated Wood ◽  
Uv Absorbance ◽  
Wood Veneer ◽  
Pull Out ◽  
Geopolymer Matrix ◽  
Pre Treatment

The bonding strength of wood veneer (Picea abies) attached between a geopolymer matrixes were investigated by means of a pull-out test. Effects of pre-treatment of wood on the bonding strength were applied whereas a strong influence of pre-treatment on bonding strength could be observed. The treatment of wood veneer showed that using wet veneer (~90% moisture content) leads to the best results compared to untreated dry (~12% moisture content) veneer. Furthermore, the effects of sodium hydroxide extraction and sodium silicate treatment were examined. The lignin UV absorbance values in treated wood, obtained by scanning ultraviolet microspectrophotometry (UMSP), do not show any significant changes in absorbance which mean that there were no complex changes in phenolic wood components, including modification of the lignin side chains. It can be said that the alkaline environment needed for geopolymer was not the main problem that limits wood (Picea abies)-geopolymer compatibility.

A New Theory for the Debonding of Discontinuous Fibers in an Elastic Matrix

1989 ◽  
Vol 170 ◽  
Author(s):  
Christopher K. Y. Leung ◽  
Victor C. Li
Keyword(s):  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Interfacial Strength ◽  
Fiber Composites ◽  
Short Fiber ◽  
Fiber Volume ◽  
Physical Reason ◽  
Pull Out

AbstractThe mechanical properties of fiber composites are strongly influenced by the debonding of fibers. When an embedded fiber is loaded from one end, debonding can occur at both the loaded end and the embedded end. Existing theories neglect the possibility of debonding from the embedded end and are thus limited in applications to cases with low fiber volume fraction, low fiber modulus, high interfacial strength/interfacial friction ratio or short fiber length. A new twoway fiber debonding theory, which can extend the validity of one-way debonding theories to all general cases, has recently been developed. In this paper, the physical reason for the occurrence of two-way debonding is discussed. The limit of validity for one-way debonding theories is considered. One-way and two-way debonding theories are then compared with respect to the prediction of composite behaviour. The determination of interfacial parameters from the fiber pull-out test will also be described.

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