检索结果-内蒙古大学图书馆

Uncertainty of Models for modulus of elasticity of Concrete in Colombian Code

ACI MATERIALS JOURNAL 2025年第2期122卷 3-14页

作者： Ortiz, Albert R. Carrillo, Julian Univ Valle Sch Civil Engn & Geomat Cali Colombia Univ Mil Nueva Granada Dept Civil Engn Bogota Colombia CEER Brussels Belgium

The modulus of elasticity of concrete is typically estimated using numerical models that consider factors such as the compressive strength of the concrete, aggregate properties, unit weight of concrete, and water-cement ratio. The most-used equation depends on the relationship between the compressive strength of the concrete and its modulus of elasticity. However, this simplified formula may provide an inaccurate estimate of the modulus of elasticity of concrete containing different types of aggregates under varying loading conditions. More sophisticated models can be used to accurately estimate the modulus of elasticity for specific applications, such as expressions involving the unit weight of concrete. This study presents a probabilistic update to the expressions used for estimating the modulus of elasticity of concrete based on an extensive database of over 2600 experimental tests from 20 different studies. Bayesian inference was used to update the currently proposed models, allowing for the determination of the expressions representing the trends of the current database along with their associated uncertainties. The updated expressions were formulated considering either the compressive strength of concrete or both the compressive strength and the unit weight as input parameters. Expressions for estimating the modulus of elasticity, considering the aggregates' origin, were also updated. This comprehensive approach enhances the accuracy and reliability of predicting the modulus of elasticity, providing valuable insights and tools for concrete structures'design and structural reliability analysis.

关键词： aggregates Bayesian model updating modulus of elasticity uncertainty quantification

来源：评论

学校读者我要写书评

暂无评论

Assessment of the modulus of Rupture and modulus of elasticity in Static Bending of Yellow Pine Earlywood and Latewood

引用

FORESTS 2025年第2期16卷 265-265页

作者： Mankowski, Piotr Karwat, Zbigniew Laskowska, Agnieszka Warsaw Univ Life Sci Inst Wood Sci & Furniture 159 Nowoursynowska St PL-02776 Warsaw Poland

The purpose of this research was to investigate the modulus of rupture (MOR) and modulus of elasticity (MOE) in the static bending of yellow pine (Pinus ponderosa Douglas ex C. Lawson) earlywood and latewood. The relationship between the properties of these wood zones and the MOR and MOE of yellow pine wood tested was determined with the methodology specified in the standards. An important element of the research was to verify the suitability of the developed method for testing the MOR and MOE of small wood samples obtained from the earlywood and latewood zone. The MOR of the earlywood was about 6% higher than the MOR of the pine wood determined using standard samples, and these differences were not statistically significant. However, the MOR of the latewood was approximately three times higher than the MOR of the pine wood determined using standard samples, and these differences were statistically significant. The MOR of the latewood was found to be 2.5 times higher than the MOR of the earlywood. The MOE of the latewood was found to be two times higher than the MOE of the earlywood. This was due to the density of particular wood zones and the dimensions of structural elements-tracheids. The maximum load (Fmax) transferred by latewood zones was four times higher than the Fmax transferred by earlywood zones. The deflection at the Fmax of the earlywood zone was 20% smaller than the deflection at the Fmax of the latewood zone.

关键词： earlywood latewood modulus of rupture modulus of elasticity Pinus ponderosa static bending strength

来源：评论

学校读者我要写书评

暂无评论

Using the appropriate modulus of elasticity of periodontal ligament matters in stress analysis of human first premolar tooth and periodontium structures

引用

SCIENTIFIC REPORTS 2025年第1期15卷 1-17页

作者： Dhammayannarangsi, Phetcharat Lampang, Sorapon Na Tompkins, Kevin A. Everts, Vincent Osathanon, Thanaphum Limjeerajarus, Chalida Nakalekha Limjeerajarus, Nuttapol Chulalongkorn Univ Fac Dent Grad Sch Dept Dent Biomat Sci Bangkok 10330 Thailand Chulalongkorn Univ Fac Dent Off Res Affairs Bangkok 10330 Thailand Univ Amsterdam Fac Dent Dept Oral Cell Biol Amsterdam Netherlands Vrije Univ Amsterdam Netherlands Chulalongkorn Univ Fac Dent Ctr Excellence Dent Stem Cell Biol Dept Anat Bangkok 10330 Thailand Chulalongkorn Univ Fac Dent Ctr Excellence Genom & Precis Dent Dept Physiol Henri Dunant Rd Bangkok 10330 Thailand

Although the modulus of elasticity of the human periodontal ligament (EPDL) values used in dentistry widely ranged from 0.01 to 175 MPa, the exact EPDL value has not been determined. This study aimed to verify whether and how EPDL values affect the stress distribution over the tooth and periodontium structures, and to determine the appropriate EPDL range. A 3D multi-component human first premolar model was created based on a cone-beam computed tomography dataset. Finite element analysis was performed to analyze stress distribution and deformation of the structures under an average Asian occlusal force with different EPDL values (0.0689-68.9 MPa). The low EPDL caused excessive PDL deformation, contributing to a non-uniform stress distribution and localized stress concentration, especially in the cementum, enamel, and dentin. With the low EPDL value, the stress magnitude was overestimated by 1,195%, potentially leading to erroneous conclusions regarding material failure and tooth movement. The EPDL value significantly affects the stress magnitude and distribution over the tooth and periodontium. The appropriate EPDL range of 0.964 +/- 0.276 MPa is suggested for human first premolars to ensure accurate and reliable FEA simulations and help avoid misinterpretation of the stress results, which could compromise orthodontic planning and restoration design.

关键词： modulus of elasticity Periodontal ligament Stress distribution Finite element analysis Multi-component model First premolar

来源：评论

学校读者我要写书评

暂无评论

New four-point bending test protocol for the strength grading of timber: relationship between local and global modulus of elasticity (MOE) of maritime pine

引用

WOOD MATERIAL SCIENCE & ENGINEERING 2024年

作者： Loko, Raoul Spero Adjovi Coureau, Jean-Luc Galimard, Philippe Cointe, Alain Aisse, Gerard Gbaguidi Univ Bordeaux I2M Talence France Univ Abomey Calavi LEMA Cotonou Benin

This study focuses on the characterisation of maritime pine according to standards EN408 and EN384 required for timber grading. A comparison of the EN408 bending test setup is performed with a new four-point bending protocol, reducing as much as possible, the effects of the shear force in the span where the deflection is measured. The study highlights difficulties to estimate accurately, the elasticity modulus of wood by using EN408 bending test setup. This is probably due to inaccuracies in the measurements of small curvatures and due to the local heterogeneities of wood. An original four-point bending test is proposed with 75% of the span of the wood beams in pure bending. This configuration clearly exhibits the convergence of measurements, in comparison to EN408 setup. The deformations generated by this new loading protocol allow a better evaluation of the bending modulus E0. Moreover, the study reveals that the proposed setup supplies an increase of elasticity modulus close to 20%. In addition, dynamic tests are also performed to characterise the Young's modulus. The experimental results reveal a better agreement between static test, using the new four-point bending configuration and dynamic method, than considering EN408 as a reference.

关键词： modulus of elasticity relationship between local and global MOE four-point bending EN384 standard timber quality

来源：评论

学校读者我要写书评

暂无评论

DETERMINATION OF FLEXURAL STRENGTH AND YOUNG'S modulus of elasticity OF ACTIVELY BENT WOOD

引用

WOOD RESEARCH 2024年第3期69卷 485-494页

作者： Herda, Roman Slivansky, Milos Brodniansky, Jan Klas, Tomas Slovak Univ Technol Bratislava Bratislava Slovakia

The article focuses on the experimental verification of wooden laths with a cross-section of 10 mm x 40 mm which were selected for active bending. The laths are made of pine wood and are 2 m in length. The research includes experimental measurements to determine the limit deformations achieved by bending the wood without chemical treatment, by applying compressive force to an originally straight beam, causing it to buckle and further deform. Ten bending tests of beams were performed, and from the same pieces, 21 tests were conducted using the four-point bending test to determine the flexural strength, and 30 tests to determine the global modulus of elasticity.

关键词： Active bending flexural strength modulus of elasticity wood

来源：评论

学校读者我要写书评

暂无评论

Determination of the modulus of elasticity by Bending Tests of Specimens with Nonuniform Cross Section

引用

EXPERIMENTAL MECHANICS 2023年第4期63卷 743-758页

作者： Gebhardt, M. Steinke, H. Slowik, V. Leipzig Univ Appl Sci Inst Expt Mech Karl Liebknecht Str 132 D-04277 Leipzig Germany Univ Leipzig Inst Anat Liebigstr 13 D-04103 Leipzig Germany

BackgroundBending tests offer technical advantages when material testing is performed to determine the modulus of elasticity. In biomechanical studies, beam-like cortical bone specimens subjected to flexural loading are usually characterized by nonuniform cross-sectional properties along the beam axis and a comparatively large spatial variation of the local material *** suitable evaluation method for determining the average modulus of elasticity within the volume of beam-like specimens with nonuniform cross section was to be *** total of 138 samples of human pelvic cortical bone were extracted and tested under flexural loading. Different methods, all based on the linear-elastic flexural theory of beams, were applied to determine the average modulus of elasticity on the basis of measured deformations, and the results were compared. Some of these methods utilized the measured midspan deflection, and others used the elastic curve obtained by digital image *** results showed that it was not appropriate to determine the average modulus of elasticity from only the measured midspan deflection. The consideration of deflections at multiple points along the beam axis is *** evaluation method based on the fitting of the analytically determined elastic curve of the beam with its nonuniform cross-sectional properties to the measured deflections is considered the most appropriate method for determining the average modulus of elasticity of the specimen.

关键词： modulus of elasticity Bending test Biomechanics Cortical bone Strain energy Digital image correlation

来源：评论

学校读者我要写书评

暂无评论

modulus of elasticity in Plywood Boards: Comparison between a Destructive and a Nondestructive Method

引用

FORESTS 2024年第9期15卷 1596页

作者： de la Cruz-Carrera, Ricardo Carrillo-Parra, Artemio Prieto-Ruiz, Jose Angel Fuentes-Talavera, Francisco Javier Ruiz-Aquino, Faustino Goche-Telles, Jose Rodolfo Univ Juarez Estado Durango UJED Programa Inst Doctorado Ciencias Agr & Forestales Durango 34113 Durango Mexico Univ Juarez Estado Durango UJED Inst Silvicultura & Ind Madera Durango 34113 Durango Mexico Univ Juarez Estado Durango UJED Fac Ciencias Forestales & Ambientales Durango 34113 Durango Mexico Univ Guadalajara UdG Ctr Univ Ciencias Exactas & Ingn CUCEI Dept Madera Celulosa & Papel Guadalajara 44100 Jalisco Mexico Univ Sierra Juarez UNSIJ Inst Estudios Ambientales Oaxaca 68725 Mexico

Nondestructive methods are a fast and accurate way to obtain information about the mechanical properties of plywood panels. The objective was to determine the modulus of rupture and compare the modulus of elasticity (MOE) in plywood boards made with Pinus spp. and Eucalyptus urograndis using the destructive method of three-point static bending and the nondestructive method of ultrasound in parallel and perpendicular directions, as well as in complete board and test specimens, both with the ultrasound method and the correlation between the variables studied. The plywood boards evaluated were 18, 25 and 30 mm nominal thickness. Five structures were evaluated using pine and pine-eucalyptus veneers. Three boards were collected per structure, and 28 specimens were made from each board (14 in a parallel direction and 14 in a perpendicular direction). The elastic modulus was determined by the ultrasound method in complete plywood boards and in specimens obtained from them using the IML Micro Hammer (R) equipment and through the conventional bending test, carried out in an Instron (R) universal mechanical testing machine. The Tukey test of means (p < 0.05) shows that in the nominal thickness of 18 mm, the modulus of elasticity by ultrasound was lower compared to the result obtained by static bending in four of the five structures in the perpendicular direction and lower in all the structures evaluated in the parallel direction;while in the nominal thickness of 25 and 30 mm, it was greater in all structures and in both directions. The results of static bending by ultrasound, in complete boards and specimens, show that the only significant difference (p < 0.05) occurs in the nominal thickness of 30 mm in the treatment made with pine-eucalyptus with urea formaldehyde resin being lower in the parallel direction and in complete boards The correlation between the modulus of elasticity determined on specimens using the nondestructive method and the destructive method was r = 0.75

关键词： modulus of rupture plywood panels modulus of elasticity static bending ultrasound

来源：评论

学校读者我要写书评

暂无评论

modulus of elasticity of blended concrete containing multiple admixtures for sustainability infrastructural material

引用

INNOVATIVE INFRASTRUCTURE SOLUTIONS 2022年第1期7卷 1-10页

作者： Kanthe, Vishvanath N. Deo, Shirish, V Murmu, Meena Guru Gobind Singh Coll Engn & Res Ctr Dept Civil Engn Nasik Maharashtra India Natl Inst Technol Dept Civil Engn Raipur Chhattisgarh India

The strength and modulus of elasticity (E) of concrete are an important aspect for design. Hence, to achieve this parameter use of industrial and agricultural byproduct can be used in concrete as partial replacement of cement. For such new triple blend concrete is needed to determine the compressive strength and ultrasonic pulse velocity (UPV), modulus of elasticity (E) and microstructure of concrete. To this objective, various mixtures of concrete were produced by replacing 20%, 30% and 40% of cement with FA and RHA blends. The modulus of elasticity was determined by various formulations such as UPV, IS and ACI. The modulus of elasticity, compressive strength and durability of triple blend concrete were improved at 20% cement replacement. As a results the concrete makes sustainable with this new triple blend.

关键词： Strength modulus of elasticity Concrete Fly ash Rice husk ash

来源：评论

学校读者我要写书评

暂无评论

modulus of elasticity and Bending Strength of Scots Pine (Pinus sylvestris L.) Wood from Commercial Thinnings

引用

FORESTS 2024年第3期15卷 567-567页

作者： Stod, Reeta Marttila, Juhani Tomppo, Laura Haapala, Antti Verkasalo, Erkki Univ Eastern Finland Doctoral Programme Sci Forestry & Technol Joensuu 80101 Finland Nat Resources Inst Finland Joensuu 80101 Finland Univ Eastern Finland Dept Tech Phys Kuopio 70211 Finland Univ Eastern Finland Dept Chem FI-80101 Joensuu Finland

The static bending properties of Scots pine (Pinus sylvestris L.) clear wood were studied using a material collected from commercial thinning forests in eastern Finland. In Myrtillus type, the modulus of elasticity and bending strength of the first thinning wood were 7.8 GPa and 66.0 MPa, respectively, whereas for more mature wood from the second thinnings, the modulus of elasticity and bending strength were 10.0 GPa and 80.3 MPa. The results were compared with final fellings, which resulted in the modulus of elasticity of 10.1 GPa and bending strength of 81.8 MPa. The bending properties of the first thinning material were low, and thus they did not indicate any potential for applications requiring high strength or stiffness and material homogeneity. On the contrary, the properties of Scots pine wood from the second commercial thinnings may be comparable with or sometimes even better than those of the final-felling wood. The results can be utilised in wood marketing, procurement, sorting, allocation to different industries and end-uses, as well as in wood processing, product sales, and branding.

关键词： bending strength clear wood harvesting mechanical properties modulus of elasticity Scots pine thinning wood materials wood industry wood products

来源：评论

学校读者我要写书评

暂无评论

Prediction of modulus of elasticity of UHPC using maximum likelihood estimation method

引用

STRUCTURES 2022年 35卷 1308-1320页

作者： Alsalman, Ali Kareem, Rahman Dang, Canh N. Marti-Vargas, Jose R. Hale, W. Micah Almaaqal Univ Coll Engn Dept Civil Engn Basra 61003 Iraq Tatum Smith Welcher Struct Engineers 3100 S Market St Rogers AR 72758 USA Univ Arkansas Bell Engn Ctr Fayetteville Dept Civil Engn 4190 Bell Engn Ctr Fayetteville Fayetteville AR 72701 USA Southern Tech Univ Shatrah Tech Inst Dept Struct Shatrah Dhi Qar Iraq Thornton Tomasetti Ho Chi Minh City Vietnam Univ Politecn Valencia Inst Concrete Sci & Technol ISCITECH Valencia Spain

modulus of elasticity (MOE) is a significant design parameter representative of the stiffness of concrete materials. In the current design practice, the determination of MOE primarily relies on empirical equations. Previous studies have recommended different equations to predict the MOE of ultra-high performance concrete (UHPC) based on a correlation with concrete compressive strength. The coefficients of these equations are dependent on the chosen empirical fits, in which the least-squares estimation (LSE) is one of the most popular fits. This study proposes a new approach by using a probabilistic method called the maximum likelihood estimation (MLE). A data set consisting of 364 data points of concrete compressive strength and MOE was developed for the MLE analysis. The negative log-likelihood is used as an indicator for the analysis. Two MOE equations are proposed. The proposed equations achieved negative log-likelihoods of 3,725 and 3,720, respectively, in comparison to 3,737 and 3,999 as the smallest and greatest negative log-likelihoods of the equations of the literature. These equations reveal that the MOE of UHPC is not proportional to the square root of concrete compressive strength as the current code equations specify for conventional concrete. The difference in the microstructure between UHPC and conventional concrete is a key factor attributing to the observation.

关键词： Ultra-high performance concrete Compressive strength modulus of elasticity Least-squares estimation Maximum likelihood estimation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：