A New Method of Screw Strength Calculation

1971 ◽  
Vol 93 (4) ◽  
pp. 1233-1238
Author(s):  
J. B. Popper
Keyword(s):  
Friction Coefficient ◽  
Tensile Load ◽  
Strength Calculation ◽  
New Method ◽  
Shear Stresses ◽  
Safety Factors ◽  
Tightening Torque ◽  
Realistic Picture ◽  
The Way

By considering several factors usually neglected, a more realistic picture of screw strength is obtained. These are: thread geometry, combined tensile and shear stresses, and uncertainty in the exact value of the friction coefficient. This uncertainty increases the tightening torque necessary to obtain a required tensile load, and reduces the effective screw strength considerably. Taking all these factors into account, the calculated screw strength is much smaller, but more realistic, so that smaller safety factors can be employed, yet more reliable designs obtained. The equations derived point the way towards two methods for increasing screw strength. These are: use of preload-indicating washers; and turning the screw back by a certain amount after the initial tightening. The first method alone can double the usable screw strength.

Cyclic Loading of Piles Using the P-Y Method

2019 ◽  
Vol 13 (2) ◽  
Author(s):  
Matt Bristow
Keyword(s):  
Cyclic Loading ◽  
Soil Depth ◽  
Large Diameter ◽  
Reference Conditions ◽  
Numerical Procedure ◽  
New Method ◽  
Shear Stresses ◽  
Applied Loading ◽  
Cyclic Degradation ◽  
Laterally Loaded

A new analytical method is presented to determine the effects of cyclic loading on laterally loaded piles. The method uses a new numerical procedure to quantify the effects of the cyclic loading at each soil depth and convert that to a set of cyclic p-y modifiers. The reduced foundation stiffness associated with the cyclic loading can be determined, including the residual static capacity and an estimate of the accumulated displacement. The new method introduces the concept of cyclic degradation damage, which is defined as sum of the cyclic degradation that is occurring at each soil depth. Cyclic degradation calculations are based on the shear stresses in the soil. Consequently, anything that causes the shear stresses to change (e.g. pile length, pile diameter, applied loading, etc.) will automatically be included in the calculation of cyclic p-y modifiers. The method has been validated by comparing the cyclic p-y curves produced using the new method with established cyclic p-y curves derived from fielding testing. The new method has also been used to investigate what happens to the cyclic p-y modifiers as one moves away from the reference conditions used to determine the established cyclic p-y curves in API RP2A (2000). The new method shows that every application (e.g. combination of cyclic loading, pile properties, and soil characteristics) has its own unique set of cyclic p-y curves, though most p-y curves fit within an upper and lower bound range. Examples are provided for large diameter monopiles.

Research on Ring Fire Diagnosis of DC Motor Based on Discrete Wavelet Lipschitz Index

2015 ◽  
Vol 9 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Tang Zhao-ping ◽  
Yang Qing-ping ◽  
Tang Shuai ◽  
Zhang Wen-sheng ◽  
Sun Jian-ping
Keyword(s):  
Dc Motor ◽  
Wavelet Function ◽  
New Method ◽  
Discrete Wavelet ◽  
Modulus Maxima ◽  
The Way

The favorable localization features of discrete wavelet provide a new method for detecting the mutational points of electric spark signal. In this paper, by means of discrete wavelet function called db5, using the way of 6 scales wavelet, analyzing the gathered electric spark signal and by extracting the modulus maxima of the 6 layers detailed signal coefficient, the signal’s mutational points were located exactly and successfully. In addition, via the modulus maxima to calculate Lipschitz index, measuring signal’s singularity, the signal’s mutational time was confirmed. The result of the simulation shows that this method can detect not only the time and size effectively if the ring fire happens but also the failure of the locomotive traction dc motor, timely and precisely. In this way, the operation safety of the train is ensured.

scholarly journals HERMENEUTIKA SEBAGAI METODE BARU DALAM MENAFSIRKAN ALQURAN

2018 ◽  
Vol 2 (2) ◽  
pp. 159
Author(s):  
Mulizar Mulizar
Keyword(s):  
The Other ◽  
New Method ◽  
Religious Groups ◽  
Other Hand ◽  
The World ◽  
The Way

This article will discuss hermeneutics as a new method of interpreting the Qur'an.The use of hermeneutics is a new thingin the world of interpretation. Some support and some reject it.The results of this study show that the use of hermeneutics in interpreting the Qur’an must be careful.In addition, This science should be placed as a complement, not as a subdivision of the science of interpretation. On the other hand, hermeneutics paves the way to contextualize the scriptures, so that they can dialogue in different spaces and times, as apologically desirable and held by many religious groups to their respective scriptures.

Axisymmetric Stress Analysis and Strength Evaluation of Bonded Shrink Fitted Joints of Circular Pipes Subjected to Internal Pressure and Tensile Loads

2000 ◽  
Author(s):  
Masahide Katsuo ◽  
Toshiyuki Sawa ◽  
Masahiro Yoneno
Keyword(s):  
Internal Pressure ◽  
Stress Analysis ◽  
Joint Strength ◽  
Tensile Load ◽  
Theory Of Elasticity ◽  
Shear Stresses ◽  
Stress Distributions ◽  
Strength Evaluation ◽  
Circular Pipes ◽  
Hollow Cylinders

Abstract This study deals with the stress analysis and the strength evaluation of a bonded shrink fitted joint of circular pipes subjected to an internal pressure and a tensile load. In the analysis, two pipes and the adhesive are replaced with finite hollow cylinders, and the stress distributions in the joint are analyzed by using the axisymmetric theory of elasticity. From the numerical calculations, the following results are obtained: (1) Both the compressive and shear stresses at the interface between the adherend and the adhesive increase as Young’s modulus of the adherend increases. (2) The stress becomes singular at the edges of the interfaces. (3) The joint strength can be evaluated using the compressive and shear stresses near the edge of the interface. In the experiments, bonded shrink fitted joints consisting of dissimilar circular pipes were manufactured, and rupture tests of the joints were carried out by applying an internal pressure, and a tensile load to the joints. From the results, the joint strength of the bonded shrink fitted joint was found to be greater than that of the shrink fitted joint. Furthermore, the numerical results are in fairly good agreement with the experimental ones.

scholarly journals Compression and Shear Fracture Analysis of Boundary Cracks Containing Water in Rock

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhensheng Yang ◽  
Fulin Li ◽  
Tianran Ma
Keyword(s):  
Stress Intensity ◽  
Friction Coefficient ◽  
Stress Intensity Factors ◽  
Underground Mining ◽  
Shear Fracture ◽  
Water Environment ◽  
Initial Crack ◽  
Open Boundary ◽  
Shear Stresses ◽  
Intensity Factors

In order to conserve the water resource during underground mining, the fracture and mechanical properties of rock are important for the stability of water-resisting layers, especially for the fracture behavior of boundary cracks containing water in rock. Considering the swelling of rock under water environment and the influence of water on rock, the stress intensity factors of modes I and II are derived for boundary cracks in rock under compressive and shear stresses. The cracks are divided into the closed and open states. The effects of the crack inclination angle, friction coefficient between crack surfaces, and initial crack length on stress intensity factors are also taken into account. The stress intensity factors for closed and open boundary cracks are verified by numerical and physical experiments, respectively, and the deviation of the results is within 5%. It is shown that pore pressure has different effects on the relationship between stress intensity factor and friction coefficient under different lateral pressures. The effect of water on crack propagation is mainly due to the deterioration of the fracture toughness of the rock. It is found that the critical coefficient λc is a key parameter to determine whether the boundary crack propagates in rock under compression-shear stress. Further studies should be performed to apply the present fracture theory to rock mass or water-resisting layers.

scholarly journals A new method to calculate the friction coefficient of ball screws based on the thermal equilibrium

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882073
Author(s):  
Lu-Chao Zhang ◽  
Li Zu
Keyword(s):  
Friction Coefficient ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Heat Dissipation ◽  
Mechanical Efficiency ◽  
New Method ◽  
Measuring System ◽  
Ball Screw ◽  
Heat Absorption ◽  
Screw Mechanism

Based on the theory of thermal transmission, this article provides a new method to acquire the friction coefficient in ball screw mechanism. While the screw is in thermal equilibrium, the heat absorption is equal to the heat dissipation. The heat absorption is able to be achieved by calculating the heat energy due to the friction at the contact area and the heat dissipation can be calculated by the law of thermodynamics. When the temperature rise is determined, the heat dissipation can be obtained and the friction coefficient in ball screw mechanism can be calculated further. In order to confirm the validity of this method, a measuring system is constructed to obtain the temperature rise of ball screws. The experimental results show that the temperature rise has the same tendency with the theoretical values depending on this model. Therefore, it can be exploited to predict the temperature rise of ball screws in the rated life cycle when the ball screw is under the condition of thermal equilibrium. Furthermore, this model can be used to evaluate the mechanical efficiency, which is an important parameter for the performance of the ball screw.

Research on the Size Design of Corrugated Box Based on the Standard Pallet Dimension

2013 ◽  
Vol 469 ◽  
pp. 205-208
Author(s):  
Shu Rong Chen ◽  
Guo Rong Cao ◽  
Xuan Zheng
Keyword(s):  
Theoretical Basis ◽  
Computer Software ◽  
New Method ◽  
Transport Cost ◽  
Experience Design ◽  
Volume Rate ◽  
Object Of Study ◽  
The Way

To solve the problems such as hand measurement, experience design and not consider area utilization of pallet, the paper researched the flow and method of size design of corrugated box when it was regularly placed in the standard pallet. The paper designed a new method to calculate the size of corrugated box which was “from outside to inside, and then from inside to outside” through optimize the way of arrangement and the number of product in which the object of study was assumed by taking product as quasi-square and cylinder and outer packaging container as corrugated box. Both the standard pallet sizes and product dimensions were considered, and it provide theoretical basis for preparing related computer software. At the same time, it ensure pallet utilization and volume rate of corrugated box, reduce transport cost farthest and realize the goal of packaging reduction.

Slipping Dynamics of Slender-Beam Payloads During Lay-Down Operations

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Shenghai Wang ◽  
Aldo Ferri ◽  
William Singhose
Keyword(s):  
Friction Coefficient ◽  
Flat Surface ◽  
New Method ◽  
Line Contact ◽  
Horizontal Position ◽  
Vertical Orientation ◽  
Dynamic Analyses ◽  
Theoretical Predictions

When laying down a long slender beam from a near-vertical orientation, to a horizontal position on a flat surface, the payload may slip and move suddenly in unintended and unpredictable ways. This occurs during crane operations when the movements of the overhead trolley and lowering of the hoist cable are not properly coordinated. The payload's unintended sliding can potentially cause damage and injure people. This paper presents static and dynamic analyses of slender-beam payload lay-down operations that establish a structured method to predict the safe conditions for lay-down operations. Also, a new method to measure the friction coefficient of surface-to-line contact is proposed. Lay-down experiments are carried out to verify the theoretical predictions.

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