Influence Of New Design Characteristics Of Wood On Determining The Longitudinal Bending Coefficient

2020 ◽  
pp. 16-20
Keyword(s):  
Elastic Modulus ◽  
Linear Method ◽  
Design Standards ◽  
New Material ◽  
Longitudinal Bending ◽  
Strength And Deformation ◽  
Design Resistance ◽  
Design Characteristics ◽  
The Stability ◽  
Wooden Structures

The standard methodology for calculating the stability of wooden rods, in which the longitudinal bending coefficient depends on the ratio of the elastic modulus to the design resistance is implemented in a linear formulation. The use of this linear method for calculating wooden structures that have a creep in time is due to studies conducted in the last century, in which it was found that this ratio for wood is constant, both during short-term loading and long-term loading. Since then, this characteristic for wood, used in calculations for the design of wooden structures, has not changed practically and the method of calculating the stability has not lost its relevance. But in the latest version of the design standards for wooden structures, the design resistances and elastic modulus for lumber, glued wood and new material made of unidirectional veneer differ depending on the strength classes, and the ratio of the elastic modulus to the design resistance becomes variable. Therefore, the formula for calculating the longitudinal bending coefficient for wooden rods with a flexibility of more than 70, left unchanged in the latest version of the norms, requires adjustment. It is proposed to change this formula taking into account the new values of the calculated strength and deformation characteristics for solid and glued wood elements. At the same time, the method of assigning calculated values of the modulus of wood elasticity is being questioned.

CALCULATION OF EFFORTS RIPS FOUNDATION BOLTS IN THE BCALCULATION OF EFFORTS RIPS FOUNDATION BOLTS IN THE BASES OF CENTRAL AND ECCENTRIC COMPRESSION COLUMNASES OF CENTRAL AND ECCENTRIC COMPRESSION COLUMN

2021 ◽  
Vol 295 (2) ◽  
pp. 32-36
Author(s):  
A.E. Svyatoshenko ◽  
◽  
Keyword(s):  
Cross Section ◽  
Software Package ◽  
Calculation Model ◽  
Neutral Axis ◽  
Continuous Section ◽  
Eccentric Compression ◽  
Engineering Technique ◽  
Section Shape ◽  
Longitudinal Bending ◽  
The Stability

An engineering technique for calculating the tearing forces in the foundation bolts in the bases of centrally compressed columns is proposed. The calculation of the forces is based on the calculation of extra-centrally compressed rods, taking into account: the influence of the cross-section shape; the initial curvature of the neutral axis of the column; random eccentricity; nonlinear steel work. The calculation of the attachment forces (Nult and Mfic) of columns on the foundation edge is based on the method of practical calculations of centrally compressed elements using the stability coefficients at central compression φ (longitudinal bending coefficients), which are calculated depending on the flexibility l. The calculation of the attachment forces for rods with different reduced flexibility was performed by FEM in the FEMAP software package, as well as analytically using fictitious forces in centrally compressed rods. To calculate the tearing forces in the foundation bolts, a calculation model is made taking into account the contact interaction of the base and the reinforced concrete base. Graphs of the effect of the flexibility of the centrally compressed rod on the tearing force in the foundation bolts at the stage of exhaustion of the bearing capacity of the column when calculating its stability as an element of a continuous section under central compression are constructed.

scholarly journals New Edible Packaging Material with Function in Shelf Life Extension: Applications for the Meat and Cheese Industries

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 562
Author(s):  
Roxana Gheorghita (Puscaselu) ◽  
Sonia Amariei ◽  
Liliana Norocel ◽  
Gheorghe Gutt
Keyword(s):  
Food Industry ◽  
Microbial Growth ◽  
Activity Index ◽  
Life Extension ◽  
Total Count ◽  
Initial Stage ◽  
Edible Packaging ◽  
New Material ◽  
The Stability ◽  
General Appearance

Nowadays, biopolymer films have gained notoriety among the packaging materials. Some studies clearly test their effectiveness for certain periods of time, with applicability in the food industry. This research has been carried out in two directions. Firstly, the development and testing of the new edible material: general appearance, thickness, retraction ratio, color, transmittance, microstructure, roughness, and porosity, as well as mechanical and solubility tests. Secondly, testing of the packaged products—slices of cheese and prosciutto—in the new material and their maintenance at refrigeration conditions for 5 months; thus, the peroxide index, color, and water activity index were evaluated for the packaged products. The results emphasize that the packaging is a lipophilic one and does not allow wetting or any changes in the food moisture. The results indicate the stability of the parameters within three months and present the changes occurring within the fourth and fifth months. Microbiological tests indicated an initial microbial growth, both for cheese slices and ham slices. Time testing indicated a small increase in the total count number over the 5-month period: 23 cfu/g were found of fresh slices of prosciutto and 27 cfu/g in the case of the packaged ones; for slices of cheese, the total count of microorganisms indicated 7 cfu/g in the initial stage and 11 cfu/g after 5 months. The results indicate that the film did not facilitate the growth of the existing microorganisms, and highlight the need to purchase food from safe places, especially in the case of raw-dried products that have not undergone heat treatment, which may endanger the health of the consumer. The new material tested represents a promising substitute for commercial and unsustainable plastic packaging.

Dielectric Elastomer as a New Material for Electrostatically Actuated Microbeams: Stability Analysis

2019 ◽  
Vol 11 (10) ◽  
pp. 1950098
Author(s):  
Mohammad Fathalilou ◽  
Pegah Rezaei-Abajelou ◽  
Afsoon Vefaghi ◽  
Ghader Rezazadeh
Keyword(s):  
Pitchfork Bifurcation ◽  
Dielectric Elastomer ◽  
Micro Electro Mechanical Systems ◽  
High Deformation ◽  
Electrostatically Actuated ◽  
Eigen Value ◽  
Deformation Ability ◽  
New Material ◽  
The Stability ◽  
Stability Regime

Due to the interesting properties such as light weight and high deformation ability, dielectric elastomer (DE) resonators can be good alternatives for conventional silicon resonant beams used in micro-electro-mechanical systems (MEMS). This paper proposes a modeling in which a pre-stretched clamped-clamped DE-based microbeam oscillating above the ground substrate is subjected to an external electrostatic pressure. Using a DE-based beam affects the total rigidity of the system, which may lead to an anticipated saddle-node or pitchfork bifurcation. Hence, the present study tries to analyze the effects of DE properties on changing the stability regime of DE-based microbeams under electrostatic actuation. The stability of the system has been investigated using an eigen-value form of the problem. The effects of DE properties including pre-stress, relative permittivity and voltage value across the electrodes on pull-in or divergence instability as well as the frequency response of the system have been investigated. Moreover, the critical values of the DE voltage as a booster of instability occurrence have been obtained in either the presence or absence of the direct current (DC) voltage. It has been found that the pre-stress and appropriate DE permittivity can provide a needed magnitude of the DE actuating voltage to alter the resonance frequency and stability positions of the structure.

Experimental Study on the Strength and Deformation Quality of Granite with Effect of High Temperature

2012 ◽  
Vol 226-228 ◽  
pp. 1275-1278 ◽  
Author(s):  
Xiao Li Xu ◽  
Feng Gao
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
High Temperature ◽  
Reference Value ◽  
Effect Of Temperature ◽  
Rock Crystal ◽  
Brittle Ductile Transition ◽  
Strength And Deformation ◽  
Temperature Strain

Experiments on granite under uniaxial compression at high temperature of 25~850°C and after high temperature of 25~1300°C were conducted to study the effect of temperature on rock strength and deformation quality. The results show that: (1) Fitting curves between temperature strain and thermal expansion coefficient with temperature are closely first order growth exponential function relation at high temperature. Temperature strain has mutagenicity after high temperature, which can not reflect rock deformation law at high temperature exactly. (2)Mechanical properties of granite weak continuously at high temperature. Compressive strength and elastic modulus show second order attenuation trend of exponential law. But mechanical properties show mutation state after high temperature, which is closely related to the alteration of rock crystal form and brittle-ductile transition. Regression curves between compressive strength and elastic modulus with temperature are closely polynomial curve. The results reflect the fundamental regulation of granite’s interior structure changing under the action of different temperature, which will provide some reference value to rock engineering involved in high temperature.

Uncertainty Model of Concrete Elastic Modulus Effect to Critical Reinforced Concrete Buckling Load

2014 ◽  
Vol 931-932 ◽  
pp. 525-528
Author(s):  
Sanguan Vongchavalitkul
Keyword(s):  
Elastic Modulus ◽  
Stability Analysis ◽  
Statistical Data ◽  
Stability Index ◽  
Buckling Load ◽  
Design Code ◽  
Critical Buckling Load ◽  
Uncertainty Model ◽  
The Stability ◽  
The Impact

There are differences in each countrys design code for concrete elastic modulus that cause uncertainty in stability analysis of critical buckling load column. This paper investigates the impact of uncertainty on concrete elastic modulus for designing of critical buckling load of building column. The statistical data on materials and applied load being collected in Thailand are used together with an investigation on the uncertainty of the concrete elastic modulus in the design code from 8 countries. Finally the Monte Carlo simulation is used to find out the stability index in term of reliability index. The results show that the uncertainty of the concrete elastic modulus plays an important role in stability analysis and should be considered in the design.

Effect of Sintering Temperature on Porous Structures and Mechanical Properties of Ti-39Nb-6Zr Alloys

2016 ◽  
Vol 848 ◽  
pp. 532-537 ◽  
Author(s):  
Ye Shao ◽  
Xiao Yun Song ◽  
Wen Jun Ye ◽  
Song Xiao Hui ◽  
Yang Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Sintering Temperature ◽  
Porous Structures ◽  
Powder Metallurgy Technique ◽  
Porous Ti ◽  
The Stability ◽  
Surrounding Bone ◽  
Compressive Tests

Titanium and its alloys have been widely used as implants replacing hard human tissues in biomedical fields. To improve the stability of implants in the surrounding bone tissues, the materials with porous structures were fabricated. In this paper powder metallurgy technique was employed to fabricate porous Ti-39Zr-6Nb (wt.%) alloys. The porous structures and mechanical properties of the porous alloys were examined by scanning electron microscopy (SEM) and compressive tests. The results showed that with increasing the sintering temperature the porosity of the alloys decreased and the compressive strength and the elastic modulus increased. The porosity of the alloys was in the range from 20.8% to 23.2%, and the pore sizes mostly centered in 10~30μm. The compressive strength and the elastic modulus were in the range from 110.4 to 292.4MPa and 4.7 to 12.4GPa respectively, which was close to human bone.

Experimental Determination of Allowable Stresses for Bamboo Guadua Angustifolia Kunth Structures

2012 ◽  
Vol 517 ◽  
pp. 76-80 ◽  
Author(s):  
Patricia Luna ◽  
Jorge Lozano ◽  
Caori Patricia Takeuchi ◽  
Mateo Gutierrez
Keyword(s):  
Elastic Modulus ◽  
Structural Material ◽  
Experimental Methodology ◽  
Allowable Stress ◽  
Design Standards ◽  
Allowable Stresses ◽  
National University ◽  
Allowable Stress Design ◽  
Main Material

The earthquake on 1999 in Armenia city (Colombia) showed the good seismic performance of structures using bamboo guadua as main material but also the mistakes caused by improper techniques of construction and the lack of parameters design for this type of structures. This work presents the experimental methodology used for the determination of allowable stresses for the design of bamboo guadua structures, used in the project "Validation of Guadua Angustifolia as a structural material for design, by the allowable stresses methodology" financed by the Ministry of Agriculture and Rural development of Colombia (Ministerio de Agricultura y Desarrollo Rural de Colombia) and developed by National University of Colombia (Universidad Nacional de Colombia) since the year 2008 when there were no allowable stress design standards for this structures in Colombia. For the determination of the allowable stresses were carried out tests of samples in compression, tension, and shear parallel to the fiber, compression perpendicular of the fiber and bending beams with bamboo guadua from three different areas of Colombia. It was found also the flexural elastic modulus for the material.

The Experiment to Research the Mudstone Interbeds which Affect the Mechanical Characters of the Layered Rock Salt

2012 ◽  
Vol 226-228 ◽  
pp. 1279-1284
Author(s):  
De Yi Jiang ◽  
Xue Qin Fan ◽  
Tao Ren ◽  
Jie Chen ◽  
Song Ren
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Rock Salt ◽  
Triaxial Compression ◽  
Salt Formation ◽  
Layered Rock ◽  
The Stability ◽  
Mechanic Property ◽  
Mechanical Characters

Since mudstone interlayer has a big influence on the mechanic property of layered rock salt, and in order to research its law, the mudstone which strength is lower than pure rock is used as a interlayer to make the regular layer of salt formation, then both the uniaxial and triaxial compression test are carried out on the layer of salt formation. The result indicates: (1) As the thickness of interlayer increases the uniaxial compressive strength and elastic modulus of layer type salt decrease. (2) On the condition that the thickness of interlayer does not change, the more the interlayer number, the stronger the uniaxial compressive strength. (3) If the total thickness of interlayer is stable and the interlayer number is same, then as the distance of interlayer increases the uniaxial compressive strength and elastic modulus of layer type salt decrease. The result provides practical value and theoretic basis on the further research of the mechanic property of layered rock soil and on the analysis of the stability of Karst underground salt cavity reservoir.

scholarly journals Study on the Influence of the Grind Percentage Over the Surface Hardness and Modulus of Elasticity of Parts Made of ABS, P6.6 and POM through Nanoindentation

2019 ◽  
Vol 56 (1) ◽  
pp. 65-70
Author(s):  
Gheorghe Radu Emil Maries ◽  
Constantin Bungau ◽  
Dan Chira ◽  
Traian Costea ◽  
Danut-Eugeniu Mosteanu
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Surface Hardness ◽  
Acrylonitrile Butadiene Styrene ◽  
The Other ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Maximum Hardness ◽  
New Material ◽  
Butadiene Styrene

This paper analyzes the indentation hardness and the indentation elastic modulus variation depending on the variation of the grind percentage of polymer, when the other factors that can influence the injection molding remain unchanged. The analyzed polymers were: acrylonitrile butadiene styrene ABS MAGNUM 3453, polyamide PA 6.6 TECHNYL AR218V30 Blak and polyoxymethylene POM EUROTAL C9 NAT. The samples that were studied had different compositions in new and grinding material. The G-Series Basic Hardness Modulus at a Depth method was used. The increase of the grind percentage of ABS (from 0 to 100 %) leads to insignificant changes in the indentation hardness, indentation modulus, and maximum force applied to samples of tested material. The maximum hardness (0.137 GPa) of PA 6.6 is recorded in the case of the sample with 80% grind content, and the maximum hardness of POM is recorded as well in the case of the sample with 80% grind content, as being 0.215 GPa. The variation of the grind content in the analyzed samples determines changes in the evaluated parameters, depending on the type of polymer. Combining the new material with grind in proportions experimentally established for each techno polymer leads to changes in their mechanical properties.

scholarly journals Research and Performance Test of New Full-Length Anchorage Material

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Shunjie Huang ◽  
Xiangrui Meng ◽  
Guangming Zhao ◽  
Yingming Li ◽  
Xiang Cheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Performance Test ◽  
Strong Stability ◽  
Full Length ◽  
Anchor Cable ◽  
New Material ◽  
Anchoring Strength ◽  
The Stability ◽  
Ultrafine Cement

It is difficult to support roadway with anchor cable in view of impact tendency in impinging liability roadway; a new material of inorganic and high-performance full-length anchoring material for anchoring cable is developed by adding several modifiers with ultrafine cement as the main material. The purpose is to improve the mechanical properties and durability of cement-based materials, improve the coordination of anchor cable support system, and ensure the stability of surrounding rock of mining roadway. The new full-length anchoring material is developed by optimizing the proportion of different components of the material, and the mechanical properties of the new material were studied. The anchoring force of resin anchoring agent, ordinary Portland cement, blank ultrafine cement, and new full-length anchoring material are tested. Based on SEM microscopic characterization, the fracture types and failure characteristics of resin anchoring agent and full-length anchoring material are researched. The results show that the optimal content of each component of the new inorganic high-performance full-length anchorage material is as follows: the content of component A is 15%, the content of component B is 3%, the content of component C is 0.2%, the content of component D is 1%, and the content of component E is 1%; the tensile test shows that the full-length anchoring material has good bonding property, high anchoring strength, strong stability, and good rock coupling. SEM microstructure and morphology analysis have showed that the new anchorage materials can fully hydrate each other, resulting in a relatively dense stone body. The new full-length anchoring material can effectively improve the anchoring force and improve the stability of the anchor cable and has significant performance advantages and good engineering applicability, and it has the advantages of lower cost and safer to use. The new material is a very good supporting material for roadway.

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