scholarly journals EFFECT OF EDGE DISTANCES ON STIFFNESS OF SHEAR-TENSION MODE IN GLULAM CONNECTIONS WITH INCLINED SCREWS

Wood Research ◽  
2021 ◽  
Vol 66 (6) ◽  
pp. 981-994
Author(s):  
YIFAN LIU ◽  
ZIYIN YAO ◽  
FEIBIN WANG ◽  
HUI HUANG ◽  
ZELI QUE
Keyword(s):  
Timber Structure ◽  
Ductile Damage ◽  
Positive Correlation ◽  
Elastic Plastic ◽  
Tension Tests ◽  
Load Carrying ◽  
Edge Distance ◽  
Significant Change ◽  
Range Of Variation ◽  
Yield Mode

The effects of edge distances on stiffness in glulam connections with inclined self-tapping screws were studied in this paper. Under four anchorage angles (A-45°, A-60°, A-75°, A-90°) and three edge distances (EG-2D, EG-4D, EG-6D) conditions, the shear-tension tests were carried out on the timber structure connections with inclined self-tapping screws, and the stiffness and other properties of the connections were tested. Based on the results, the effects of edge distances on stiffness in joints were quantified using the equivalent energy elastic-plastic (EEEP) model. The results showed that the edge distances had a certain impact on the yield mode and load-carrying performance of the joints. Within a certain range of variation, as the edge distance increased, the stiffness of the connections increased gradually, showing a positive correlation. The stiffness of specimen EG-2D is 4.41 kN·mm-1. The stiffness of specimen EG-4D is 10.04 kN·mm-1, which increasesby 128% compared with the specimen EG-2D. The stiffness of specimen EG-6D is 12.08 kN·mm-1, which increases by 174% compared with the specimen EG-2D. However, the ductility coefficient, yielding load, and energy dissipatinghave no significant change. Within a reasonable edge distance, only ductile damage occurred.

Experimental Study on the Collapse Strength of Narrow Stiffened Panels

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Ming Cai Xu ◽  
C. Guedes Soares
Keyword(s):  
Carrying Capacity ◽  
Longitudinal Direction ◽  
Strain Gauges ◽  
Load Carrying Capacity ◽  
Stiffened Panels ◽  
Modes Of Failure ◽  
Collapse Strength ◽  
Tension Tests ◽  
Load Carrying ◽  
Collapse Behavior

The results of five tests on narrow stiffened panels under axial compression until collapse and beyond are presented to investigate the collapse behaviors of stiffened panels. Tension tests were used to evaluate the material properties of the stiffened panels. The tests were made on panels with two half bays plus one full bay in the longitudinal direction. Initial loading cycles were used to eliminate the residual stresses of the stiffener panels. The strain gauges were set on the plates and the stiffeners to record the strain histories. The displacement load relationship was established. The collapse behavior, modes of failure and load-carrying capacity of the stiffened panels are investigated with the experiment.

scholarly journals Effect of Strain Hardening on Elastic-Plastic Contact of a Deformable Sphere against a Rigid Flat under Full Stick Contact Condition

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Biplab Chatterjee ◽  
Prasanta Sahoo
Keyword(s):  
Strain Hardening ◽  
Kinematic Hardening ◽  
Contact Condition ◽  
Isotropic Hardening ◽  
Contact Conditions ◽  
Elastic Plastic ◽  
Finite Element Software ◽  
Hardening Models ◽  
Load Carrying ◽  
Contact Parameters

The present study considers the effect of strain hardening on elastic-plastic contact of a deformable sphere with a rigid flat under full stick contact condition using commercial finite element software ANSYS. Different values of tangent modulus are considered to study the effect of strain hardening. It is found that under a full stick contact condition, strain hardening greatly influences the contact parameters. Comparison has also been made between perfect slip and full stick contact conditions. It is observed that the contact conditions have negligible effect on contact parameters. Studies on isotropic and kinematic hardening models reveal that the material with isotropic hardening has the higher load carrying capacity than that of kinematic hardening particularly for higher strain hardening.

scholarly journals Contact Analysis and Static Load Carrying Capacity of Planetary Roller Screw Mechanism

2020 ◽  
Author(s):  
Nam Su Kim ◽  
Kyongho Kim ◽  
Sinhyok Jong
Keyword(s):  
Finite Element ◽  
Contact Stress ◽  
Carrying Capacity ◽  
Static Load ◽  
Load Capacity ◽  
Load Carrying Capacity ◽  
Elastic Plastic ◽  
Load Carrying ◽  
Roller Screw ◽  
Screw Mechanism

Abstract This paper aims to investigate the contact characteristics and static load carrying capacity of planetary roller screw mechanism (PRSM). Compared to the ball screw mechanism, the advantages of the PRSM are high stiffness, high load capacity, long travel life and compact structure, etc., since the PRSM possesses more contact points than ball screws in a comparable size. The actuated load is carried through the threaded surface contacts of the screw, the rollers and the nut and the contact characteristics of these components are very important for studying the wear, transmission accuracy and efficiency of a PRSM. Prior work has neglected to take a fundamental approach towards understanding the elastic-plastic contact characteristics of threaded surfaces under high loads and it is closely related to the static load carrying capacity of PRSM. Accordingly, in this paper, the contact characteristics of PRSM under the different working loads are modeled based on Hertz contact theory and the calculation formulas between normal force of thread turns and the elastic-plastic contact stress and deformation are derived. Then, it goes further to derive a calculation method of static load carrying capacity of PRSM based on simplified model of static load distribution. Finally, a verification model is developed by finite element method (FEM) to perform contact stress and strain analysis of PRSM. Besides, through the comparison of the results between the theory model and ANSYS Workbench finite element model verify the reliability of the theory.

Experimental Study on the Collapse Strength of Narrow Stiffened Panels

2011 ◽  
Author(s):  
Mingcai Xu ◽  
C. Guedes Soares
Keyword(s):  
Ultimate Strength ◽  
Longitudinal Direction ◽  
Strain Gauges ◽  
Load Carrying Capacity ◽  
Stiffened Panels ◽  
Modes Of Failure ◽  
Collapse Strength ◽  
Tension Tests ◽  
Load Carrying ◽  
Strength Behavior

The results of four tests on narrow stiffened panels under axial compression until collapse and beyond are presented to investigate the ultimate strength of stiffened panels. Tension tests are used to evaluate the material properties of the stiffened panels. The tests are made on panels with two half bays plus one full bay in the longitudinal direction. Initial loading cycles were used to relief the residual stresses of the stiffener panels. The strain gauges are set on the plates and stiffeners to record the distribution of strain. The displacement load relationship is established. The ultimate strength behavior, modes of failure and load-carrying capacity of the stiffened panels are investigated with the experiment.

Influences of cultivar, cultivation year and fertilizer rate on amount of protein groups and amount and size distribution of mono- and polymeric proteins in wheat

2003 ◽  
Vol 140 (3) ◽  
pp. 275-284 ◽  
Author(s):  
E. JOHANSSON ◽  
M. L. PRIETO-LINDE ◽  
G. SVENSSON ◽  
J. Ö. JÖNSSON
Keyword(s):  
Size Distribution ◽  
Protein Concentration ◽  
Significant Positive Correlation ◽  
Environmental Influences ◽  
Sodium Dodecyl ◽  
Gluten Strength ◽  
Fertilizer Rate ◽  
Positive Correlation ◽  
Protein Components ◽  
Range Of Variation

Influences of cultivar and environment, i.e. cultivation year and fertilizer rate, on amount of protein groups and amount and size distribution of mono- and polymeric proteins, were investigated in four sets of wheat (Triticum aestivum L.). The cultivars were chosen in order to obtain a high range of variation in protein concentration and gluten strength. Environmental influences on protein concentration and gluten strength were investigated, as well as relations between variation in protein concentration and gluten strength and variation in protein groups and amount and size distribution of mono- and polymeric proteins.The results showed that cultivar and environmental influences giving rise to variation in protein concentration also gave rise to variation in most of the investigated protein components. Protein concentration was significantly positively correlated to the total amounts of glutenins and gliadins and amounts of most mono- and polymeric proteins. However, the correlation with the amount of gliadins and sodium dodecyl sulphate (SDS)-soluble mono- and polymeric proteins were often higher than the correlation to the glutenins and the SDS-insoluble mono- and polymeric proteins. Cultivar influences giving rise to variation in gluten strength were found to influence the relation between SDS-soluble and -insoluble polymeric proteins, leading to a significant positive correlation between the gluten strength and the percentage of total unextractable polymeric protein (TUPP) in the total polymeric protein and large unextractable polymeric protein (LUPP) in the total large polymeric protein. Environmental variation in gluten strength was found to be significantly positively correlated to SDS-insoluble proteins and negatively correlated to SDS-soluble proteins. This also led to a significant positive correlation with the percentage of LUPP and/or TUPP.

Spherical Elastic-Plastic Waves

1995 ◽  
Vol 1 (3) ◽  
pp. 345-360 ◽  
Author(s):  
Franz Ziegler ◽  
Hans Irschik ◽  
Helmut Holl
Keyword(s):  
Elastic Wave ◽  
Thermal Stresses ◽  
Constitutive Relations ◽  
Wave Pattern ◽  
Small Cells ◽  
Ductile Damage ◽  
Dissipated Energy ◽  
Time Step ◽  
Elastic Plastic ◽  
Spherical Waves

By examining the micro-mechanical foundation of thermoplasticity and ductile damage, an indica tion of its continuum effects, which are to be considered as material imperfections of the ideal linear elastic background structure, is given. This approach, originally developed for structural vibrations, was recently extended to include uniaxial propagating waves. This method suggests pursuing the initially elastic wave until it produces plastic deformation, which means a distortion and thus a source that emits elastic waves. Since the spherical waves in such a procedure must be derived from nondispersive D'Alembert wave functions, nonlocal sources extending from each of the plastic sources to infinity are ignited as well and contribute to the elastic wave pattern. The contribution of thermal stresses resulting from the rapid changes of temperature that are produced under adiabatic conditions by the dissipated energy are included in the general analysis, but the material parameters are kept constant. In terms of the control theory of distributed parameter time variant systems, a typical feedback mechanism is constructed. By dividing space into sufficiently small cells, the dis tortion may be kept constant during a yielding event, and by superposition of all the waves, the exact solution, including plastic wave fronts, is obtained. By means of the constitutive relations, strength and distribution of the internal sources are updated after each time step. One major aspect of the procedure is the consideration of the constitutive relations at a late stage of the solution routine. Yet all the merits of the elastic dynamic Green's function are taken into account. The nonlinear spherical wave problem resulting from an explosion in a cavity is solved for the special case of an ideal elastic plastic material under isothermal conditions and without any ductile damage to check the resulting wave pattern by comparison with previously published ones.

scholarly journals Choice of vehicles for transportation of agricultural production

2018 ◽  
pp. 116-124
Author(s):  
V.O. Timochko ◽  
R.I. Padiuka
Keyword(s):  
Carrying Capacity ◽  
Agricultural Production ◽  
Entire Range ◽  
Block Diagram ◽  
Rolling Stock ◽  
Load Carrying Capacity ◽  
The Road ◽  
Load Carrying ◽  
Loading And Unloading ◽  
Range Of Variation

Agricultural cargoes, by their physical and mechanical pro-perties, loading and unloading methods; conditions of transportation and sto-rage, the possibility of using the load carrying capacity of the rolling stock, their preservation during transportation, the degree of danger during loading, unloading and transportation cover the entire range of variation. This entails the need to attract practically all types of transportation means for their transportation. The structure of the order for transportation is substantiated, the types of agricultural cargoes analyzed and a matrix of the choice of the type of the vehicle according to the characteristics of the cargo is constructed, which enables us to substantiate the expediency of using the vehicles. A block diagram of the algorithm for choosing the types of vehicles for the transportation of agricultural cargoes has been developed to take into account the main constraints, namely the characteristics of the cargo, the restrictions imposed by the road conditions of the route and the peculiarities of loading, the urgency of transportation and the size of the consignment. To execute a pre-ordered order, a vehicle is selected that satisfies the constraints and ensures a minimum freight cost.

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