检索结果-内蒙古大学图书馆

18th International Brick and Block Masonry Conference, IB2MaC 2024

作者： Kahangi Shahreza, Seyedmohammad Bayat Pour, Mohsen Abdul Hamid, Akram Molnár, Miklós Division of Structural Engineering Department of Building and Environmental Technology Lund University John Ericssons Väg 1 SE Lund223 63 Sweden Division of Building Physics Department of Building and Environmental Technology Lund University John Ericssons Väg 1 SE Lund223 63 Sweden

ISBN: (纸本)9783031733130

In Sweden, cavity walls constructed with autoclaved aerated concrete (AAC) inner leaves and clay brick outer leaves were a common design choice during the 1950s to 1970s. These walls often result in relatively extensive heat losses, leading to reduced indoor thermal comfort. Further, moisture-related issues like frost damage and interior dampness are reported for this wall type. This indicates the importance of enhancing the hygric and thermal performance of such walls. Since preservation of the protected facade due to heritage values limits external interventions, interior insulation becomes a primary focus for energy efficiency improvements. This study aims to explore various maintenance and renovation measures to enhance the performance of these walls, namely a) repointing the outer leaf (face bricks), b) adding interior insulation with different properties, and c) combining interior insulation with repointing. The study employs hygrothermal simulations for Gothenburg, the location with one of the highest exposure to wind-driven rain (WDR) in Sweden. The results highlight that an efficient way to improve the wall condition, a balance between moisture accumulation and heat loss, is to add vapor-open insulation followed by repointing, especially for walls in a deficient condition. Repointing alone effectively reduces moisture accumulation for cavity walls with brick masonry in a deficient condition, with a limited impact on improving thermal comfort. XPS insulation, a vapor-tight system, reduces heat loss but increases moisture in the AAC layer, posing potential moisture-related issues. Adding capillary-active insulation followed by repointing improves thermal comfort without significant moisture accumulation in the AAC layer. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Autoclaved aerated concrete

来源：评论

学校读者我要写书评

暂无评论

An approach based on multiquadric radial basis functions for smooth trajectory planning of robotic manipulators with kinematic constraints

引用

Nonlinear Dynamics 2025年 1-19页

作者： Bendali, Nadir Scalera, Lorenzo Sundaram, Arunachalam Said, Abderrezak Gasparetto, Alessandro Faculty of Science and Technology Khemis Miliana University Road of Theniet El Had Khemis Miliana44225 Algeria Structural Mechanics Research Laboratory Department of Mechanical Engineering University Blida-1 BP 270 Route Soumâa Blida09000 Algeria Polytechnic Department of Engineering and Architecture University of Udine via delle Scienze 206 Udine33100 Italy School of Science Engineering and Environment University of Salford SEE Building SalfordM5 4WT United Kingdom

This paper introduces a novel approach for planning smooth trajectories of robotic manipulators by leveraging multiquadric radial basis functions (MQ-RBFs). The proposed approach aims to achieve optimal trajectories by minimizing a multi-objective function that accounts for both time and jerk optimization. The MQ-RBF interpolation technique ensures that the trajectory meets velocity, acceleration, and jerk limits, while ensuring jerk continuity. Comparative evaluations are conducted in two cases: with and without optimization. In the first case, the MQ-RBF interpolation approach is compared with various RBF interpolation models. In the second case, the MQ-RBF trajectory approach is compared with alternative state-of-the-art trajectory planning techniques, such as fifth-order B-splines and trigonometric spline functions, for generating optimal time-jerk trajectories for 6-joint robotic manipulators using optimization algorithms. Numerical and experimental results demonstrate the superior performance of the proposed technique in efficiently planning smooth trajectories compared to existing trajectory planning approaches and validate its effectiveness across various scenarios. © The Author(s) 2025.

关键词： Interpolation

来源：评论

学校读者我要写书评

暂无评论

High-Performance Masonry Walls for Energy and Resource Efficient building Envelopes 18th

High-Performance Masonry Walls for Energy and Resource Effic...

引用

18th International Brick and Block Masonry Conference, IB2MaC 2024

作者： Molnár, Miklós Niklewski, Jonas Björnsson, Ivar Carlsvärd, Christian Gustavsson, Tomas Division of Structural Engineering Department of Building and Environmental Technology Lund University John Ericssons Väg 1 Lund223 63 Sweden Weber Saint-Gobain Sweden AB P.O. Box 415 Sollentuna191 24 Sweden Tomas Gustavsson Konstruktioner AB Adelgatan 1B Lund223 50 Sweden

ISBN: (纸本)9783031733093

Externally bonded reinforcement (EBR) was used to increase load bearing capacity of light weight aggregate concrete (LWA) masonry walls subjected to eccentric axial compression. Ladder type masonry reinforcement, high strength steel wire strips and glass fiber mesh were used for strengthening of eleven, 2.4 m high, 0.5 m long and 0.1 m thick walls. The reinforcement was applied on the dry wall surface and subsequently embedded in mortar, a procedure that saves labor time. The walls were subjected to axial eccentric loading, with an eccentricity to wall thickness ratio between 0.18 and 0.20. Six walls failed through local compression (crushing) at the loading plate, four in flexural compression while one in flexural tension. The walls exhibited limited second order deflections, which partly explains the high frequency of compressive failures. While the experimentally and analytically determined deflection of the walls shows good agreement, the same does not apply to the bending moments. The experimentally deduced bending moment capacity was significantly larger than the analytically deduced bending moment capacity. The possible reasons for this difference are discussed. By using EBR, the vertical load bearing capacity of LWA masonry walls can be enhanced by 30–150%. Compared to existing masonry wall solutions, the thickness of load bearing LWA masonry walls strengthened with EBR can be reduced by 40–60 mm, down to a thickness of 110 mm. The new technique is currently tested in three real-world pilot projects. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Concrete aggregates

来源：评论

学校读者我要写书评

暂无评论

A parallel parameterized level set method for large-scale structural topology optimization under design-dependent load

引用

Computer Methods in Applied Mechanics and engineering 2025年 443卷

作者： Wei, Peng Cheng, Ben Lin, Haoju Liu, Hui State Key Laboratory of Subtropical Building Science School of Civil Engineering and Transportation South China University of Technology Guangzhou510641 China Department of Engineering Mechanics School of Civil Engineering Wuhan University Wuhan430072 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian116081 China State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan430074 China

This paper proposes a topology optimization framework for three-dimensional continuum structures subjected to design-dependent loads, including gravity, centrifugal, and hydrostatic pressure loads. First, this study utilizes the parameterized level set method (PLSM) with unstructured meshes to effectively handle complex structural shapes and boundary conditions. Second, this work employs parallel computing techniques and uses the shape function as the basis function in PLSM to significantly enhance computational efficiency. Additionally, this study comprehensively analyzes design-dependent loads and addresses topology optimization of large-scale structures under complex load conditions. This study overcomes the lack of research on complicated 3D design-dependent load problems. It aims to broaden the application of topology optimization techniques, making them more applicable to engineering practices, such as large-scale underwater structures. Finally, several 3D examples demonstrate the proposed framework's efficiency, stability, and ability to generate innovative structural designs. © 2025 Elsevier B.V.

关键词： Shape optimization

来源：评论

学校读者我要写书评

暂无评论

AN ORTHOGONAL RESIDUAL PROCEDURE FOR NONLINEAR FINITE-ELEMENT EQUATIONS

引用

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN engineering 1995年第5期38卷 823-839页

作者： KRENK, S Department of Building Technology and Structural Engineering University of Aalborg Aalborg Denmark

A general and robust solution procedure for non-linear finite element equations with limit points is developed. At each equilibrium iteration the magnitude of the load is adjusted such that the residual force is orthogonal to the current displacement increment from the last equilibrium state. The method implements the physical condition that the orthogonal residual force will neither increase nor decrease the magnitude of the current displacement increment vector. The orthogonality condition is formulated directly in terms of conjugate variables and therefore does not contain any scaling parameters. Passage of load and displacement limit points is discussed as well as the relation to line search, minimum residual, and are-length methods. The method is illustrated by two examples.

关键词： NUMERICAL ALGORITHMS PATH FOLLOWING TECHNIQUE NONLINEAR EQUATIONS NONLINEAR FINITE ELEMENTS

来源：评论

学校读者我要写书评

暂无评论

Fatigue analysis and testing of adhesive joints

引用

engineering FRACTURE MECHANICS 1996年第6期53卷 859-872页

作者： Krenk, S Jonsson, J Hansen, LP Department of Building Technology and Structural Engineering Aalborg University Aalborg Denmark

The fatigue resistance of a single-lap aluminium adhesive joint to cyclic loading in combined shear and bending mode is investigated by nonlinear finite element analysis and crack propagation experiments. The epoxy adhesive is modelled by an elasto-plastic overlay material model. The initial cycles build up a residual stress state, leading to nearly linear material behaviour in the following cycles. Fatigue crack propagation is modelled by removing adhesive elements. Two series of experiments with one-sided cyclic load were carried out. The crack length was monitored by measuring the bending compliance around the end of the overlap with clip-gauges. The crack length is determined as a simple linear function of the measured compliance. The experiments show nearly constant rate crack growth until failure, with no appreciable crack initiation period. The rate of crack growth is proportional to the stress level to the power m = 6.2. Fatigue life results are given in the form of S-N curves for adhesive thickness of 0.1 and 0.3 mm. There is no systematic influence of the thickness of the adhesive on the fatigue life. This supports the use of a crack propagation and fatigue life criterion formulated in terms of the energy release rate.

关键词： Adhesive joints

来源：评论

学校读者我要写书评

暂无评论

A GENERAL FORMAT FOR CURVED AND NONHOMOGENEOUS BEAM ELEMENTS

引用

COMPUTERS & STRUCTURES 1994年第4期50卷 449-454页

作者： KRENK, S Department of Building Technology and Structural Engineering University of Aalborg Aalborg Denmark

A general format, based on equilibrium states, is developed for the stiffness matrix of elastic beam elements. The stress states are described relative to the line connecting the element end points, whereby the external work takes a common form independent of the shape of the beam element. The resulting stiffness matrix is obtained by simple, explicit combinations of a small number of stress energy terms. Examples include a Timoshenko beam with flexible joints, a beam of variable cross-section, and a strongly curved circular beam.

关键词： structural analysis

来源：评论

学校读者我要写书评

暂无评论

A PROFILE SOLVER IN C FOR FINITE-ELEMENT EQUATIONS

引用

COMPUTERS & STRUCTURES 1994年第4期52卷 743-748页

作者： HEDEDAL, O KRENK, S Department of Building Technology and Structural Engineering University of Aalborg 9000 Aalborg Denmark

This paper presents an efficient, pointer based profile solver with standard matrix indexing. Constrained equations Ax = b where x contains known and unknown values are solved and the full vectors x and b are obtained. Pseudo-code algorithms are formulated for a row oriented form of the LDL(T) factorization and implemented directly as a C code. The solver is implemented in C because of the close relation between two-dimensional arrays and pointers which makes it possible to write a clear and efficient code.

关键词： structural analysis

来源：评论

学校读者我要写书评

暂无评论

A DUAL ORTHOGONALITY PROCEDURE FOR NONLINEAR FINITE-ELEMENT EQUATIONS

引用

COMPUTER METHODS IN APPLIED MECHANICS AND engineering 1995年第1-4期123卷 95-107页

作者： KRENK, S HEDEDAL, O Department of Building Technology and Structural Engineering Aalborg University DK-9000 Aalborg Denmark

In the orthogonal residual procedure for solution of non-linear finite element equations, the load is adjusted in each equilibrium iteration to satisfy an orthogonality condition to the current displacement increment. It is shown here that the quasi-Newton formulation of the orthogonal residual method consists of a simple one-term correction of the displacement subincrement, and that this correction leads to orthogonality between the corrected displacement subincrement and the current increment of the internal force vector, thus defining a dual orthogonality algorithm. It is demonstrated how the algorithm can be implemented to combine a single update of the stiffness matrix for each load increment in normal circumstances with full updates locally if increasing stiffness is encountered. The algorithm is illustrated by examples.

关键词： Numerical methods

来源：评论

学校读者我要写书评

暂无评论

Force lines in plane stress

引用

JOURNAL OF ELASTICITY 1997年第2期47卷 167-178页

作者： Rathkjen, A Department of Building Technology and Structural Engineering University of Aalborg DK-9000 Aalborg Denmark

A state of plane stress is illustrated by means of two families of curves, each family representing constant values of a derivative of Airy's stress function. The two families of curves farm a map giving in the first place an overall picture of regions of high and low stress, and in the second place, the map comprises a complete graphic representation of the stress at any point.

关键词： stress vectors Airy's stress function

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：