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1 – 10 of 127Ahmad Chihadeh and Michael Kaliske
This paper aims to introduce a method to couple truss finite elements to the material point method (MPM). It presents modeling reinforced material using MPM and describes how to…
Abstract
Purpose
This paper aims to introduce a method to couple truss finite elements to the material point method (MPM). It presents modeling reinforced material using MPM and describes how to consider the bond behavior between the reinforcement and the continuum.
Design/methodology/approach
The embedded approach is used for coupling reinforcement bars with continuum elements. This description is achieved by coupling continuum elements in the background mesh to the reinforcement bars, which are described using truss- finite elements. The coupling is implemented between the truss elements and the continuum elements in the background mesh through bond elements that allow for freely distributed truss elements independent of the continuum element discretization. The bond elements allow for modeling the bond behavior between the reinforcement and the continuum.
Findings
The paper introduces a novel method to include the reinforcement bars in the MPM applications. The reinforcement bars can be modeled without any constraints with a bond-slip constitutive model being considered.
Originality/value
As modeling of reinforced materials is required in a wide range of applications, a method to include the reinforcement into the MPM framework is required. The proposed approach allows for modeling reinforced material within MPM applications.
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Babak Lotfi and Bengt Ake Sunden
This study aims to computational numerical simulations to clarify and explore the influences of periodic cellular lattice (PCL) morphological parameters – such as lattice…
Abstract
Purpose
This study aims to computational numerical simulations to clarify and explore the influences of periodic cellular lattice (PCL) morphological parameters – such as lattice structure topology (simple cubic, body-centered cubic, z-reinforced body-centered cubic [BCCZ], face-centered cubic and z-reinforced face-centered cubic [FCCZ] lattice structures) and porosity value ( ) – on the thermal-hydraulic characteristics of the novel trussed fin-and-elliptical tube heat exchanger (FETHX), which has led to a deeper understanding of the superior heat transfer enhancement ability of the PCL structure.
Design/methodology/approach
A three-dimensional computational fluid dynamics (CFD) model is proposed in this paper to provide better understanding of the fluid flow and heat transfer behavior of the PCL structures in the trussed FETHXs associated with different structure topologies and high-porosities. The flow governing equations of the trussed FETHX are solved by the CFD software ANSYS CFX® and use the Menter SST turbulence model to accurately predict flow characteristics in the fluid flow region.
Findings
The thermal-hydraulic performance benchmarks analysis – such as field synergy performance and performance evaluation criteria – conducted during this research successfully identified demonstrates that if the high porosity of all PCL structures decrease to 92%, the best thermal-hydraulic performance is provided. Overall, according to the obtained outcomes, the trussed FETHX with the advantages of using BCCZ lattice structure at 92% porosity presents good thermal-hydraulic performance enhancement among all the investigated PCL structures.
Originality/value
To the best of the authors’ knowledge, this paper is one of the first in the literature that provides thorough thermal-hydraulic characteristics of a novel trussed FETHX with high-porosity PCL structures.
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Yongliang Zhang, Jibei Ma, Xingchong Chen and Yun Wang
Under different ground motion excitation modes, the spatial coupling effect of seismic response for the arch bridge with thrust, seismic weak parts and the internal force…
Abstract
Purpose
Under different ground motion excitation modes, the spatial coupling effect of seismic response for the arch bridge with thrust, seismic weak parts and the internal force components of the control section of main arch ribs are analyzed.
Design/methodology/approach
Taking a 490 m deck type railway steel truss arch bridge as the background, the dynamic calculation model of the whole bridge was established by SAP2000 software. The seismic response analyses under one-, two- and three-dimension (1D, 2D and 3D) uniform ground motion excitations were carried out.
Findings
For the steel truss arch bridge composed of multiple arch ribs, any single direction ground motion excitation will cause large axial force in the chord of arch rib. The axial force caused by transverse and vertical ground motion excitation in the chord of arch crown area is 1.4–3.6 times of the corresponding axial force under longitudinal seismic excitation. The in-plane bending moment caused by the lower chord at the vault is 4.2–5.5 times of the corresponding bending moment under the longitudinal seismic excitation. For the bottom chord of arch rib, the arch foot is the weak part of earthquake resistance, but for the upper chord of arch rib, the arch foot, arch crown and the intersection of column and upper chord can all be the potential earthquake-resistant weak parts. The normal stress of the bottom chord of the arch rib under multidimensional excitation is mainly caused by the axial force, but the normal stress of the upper chord of the arch rib is caused by the axial force, in-plane and out of plane bending moment.
Originality/value
The research provides specific suggestions for ground motion excitation mode and also provides reference information for the earthquake-resistant weak part and seismic design of long-span deck type railway steel truss arch bridges.
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David Marschall, Sigfrid-Laurin Sindinger, Herbert Rippl, Maria Bartosova and Martin Schagerl
Laser sintering of polyamide lattice-based lightweight fairing components for subsequent racetrack testing requires a high quality and a reliable design. Hence, the purpose of…
Abstract
Purpose
Laser sintering of polyamide lattice-based lightweight fairing components for subsequent racetrack testing requires a high quality and a reliable design. Hence, the purpose of this study was to develop a design methodology for such additively manufactured prototypes, considering efficient generation and structural simulation of boundary conformal non-periodic lattices, optimization of production parameters as well as experimental validation.
Design/methodology/approach
Multi-curved, sandwich structure-based demonstrators were designed, simulated and experimentally tested with boundary conformal lattice cells. The demonstrator’s non-periodic lattice cells were simplified by forward homogenization processes. To represent the stiffness of the top and bottom face sheet, constant isotropic and mapped transversely isotropic simulation approaches were compared. The dimensional accuracy of lattice cells and demonstrators were measured with a gauge caliper and a three-dimensional scanning system. The optimized process parameters for lattice structures were transferred onto a large volume laser sintering system. The stiffness of each finite element analysis was verified by an experimental test setup including a digital image correlation system.
Findings
The stiffness prediction of the mapped was superior to the constant approach and underestimated the test results with −6.5%. Using a full scale fairing the applicability of the development process was successfully demonstrated.
Originality/value
The design approach elaborated in this research covers aspects from efficient geometry generation over structural simulation to experimental testing of produced parts. This methodology is not only relevant in the context of motor sports but is transferrable for all additively manufactured large scale components featuring a complex lattice sub-structure and is, therefore, relevant across industries.
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This research addresses the diverse characteristics of existing railway steel bridges in China, including variations in construction age, design standards, structural types…
Abstract
Purpose
This research addresses the diverse characteristics of existing railway steel bridges in China, including variations in construction age, design standards, structural types, manufacturing processes, materials and service conditions. It also focuses on prominent defects and challenges related to heavy transportation conditions, particularly low live haul reserves and severe fatigue problems.
Design/methodology/approach
The study encompasses three key aspects: (1) Adaptability assessment: It begins with assessing the suitability of existing railway steel bridges for heavy-haul operations through comprehensive analyses, experiments and engineering applications. (2) Strengthening: To combat frequent crack defects in the vertical stiffener end structure of girder webs, fatigue performance tests and reinforcement scheme experiments were conducted. These experiments included the development of a hot-spot stress S-N curve for this structure, validating the effectiveness of methods like crack stop holes, ultrasonic hammering and flange angle steel. (3) Service life extension: Research on the cruciform welded joint structure (non-fusion transfer type) focused on fatigue performance over the long life cycle. This led to the establishment of a fatigue S-N curve, enhancing Chinese design codes.
Findings
The research achieved several significant outcomes: (1) Successful implementation of strengthening and retrofitting measures on a 64-m single-span double-track railway steel truss girder on an existing heavy-duty line. (2) Post-reinforcement, a substantial 26% to 32% reduction in live haul stress on bridge members was achieved. (3) The strengthening and retrofitting efforts met design expectations, enabling the bridge to accommodate vehicles with a 30-ton axle haul on the railway line.
Originality/value
This research systematically tackles challenges and defects associated with Chinese existing railway steel bridges, providing valuable insights into adaptability assessment, strengthening techniques and service life extension methods. Furthermore, the development of fatigue S-N curves and the successful implementation of bridge enhancements have practical implications for improving the resilience and operational capacity of railway steel bridges in China.
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Marcus Vinicius de Miranda Castro, Mariana Lopes de Araújo, Andréia Miguens Ribeiro, Gisela Demo and Pedro Paulo Murce Meneses
The strategic human resource management (SHRM) emerged in the middle of the 1980s and is currently seen as a relevant research and practical field in the area of business…
Abstract
Purpose
The strategic human resource management (SHRM) emerged in the middle of the 1980s and is currently seen as a relevant research and practical field in the area of business administration (Kaufman, 2015). Its academic relevance has been receiving international attention due to the importance of the strategic performance of human resource management (HRM) (Jackson, Schuler, & Jiang, 2014). It is possible to define SHRM as a vertical connection between HRM practices and international strategy and horizontally as the congruence among the several human resource practices (Wright & McMahan, 1992).
Design/methodology/approach
Taking into consideration the emerging research gaps in the area, the necessity to bring to attention the implementation of policies and strategic practices of human resource management became prominent. Our study characterizes the national scenario regarding this specific research theme. For such, we developed a bibliometric review of national journals in the area of business administration with level Qualis B2 [1] or above, described the institutionalization of the research in Brazil and established a sociogram with research relationship networks in the country.
Findings
Between 1997 and 2017, only 19 articles on the implementation of SHRM were published in the 32 journals researched. The characterization of the studies indicates a predominance of qualitative articles, which adopt as methodological approach the case study, and most of them use interviews and content analysis as techniques of data collection and analysis, respectively. The use of such investigation tools is in line with the nature of the phenomenon studied. The scenario indicates that the implementation of SHRM is still a developing theme in Brazil.
Research limitations/implications
There is a lack of studies that combine the use of qualitative and quantitative approaches and focus on public organizations. Besides, the results indicate the need to diversify the methodological approaches used. Regarding the institutionalization of research in Brazil, it is possible to notice the growth of research groups investigating SHRM, even though their only focus does not rely on implementation. The academic production regarding the theme is regionally located in the state of São Paulo, even though academic production is also to be found in a decentralized way in the country, with rare networks.
Practical implications
This way, the main contribution of this article is the accomplishment of the first bibliometric review regarding the implementation of SHRM in Brazil, showing the scientific community that the theme still presents a gap to be explored in national studies and showing human resource professionals and the society that the transformational switch of human management to organizational outcomes – despite prolific in the academia – still has not been realized in practice.
Social implications
In the articles analyzed, the most common finding was that the effective implementation of SHRM and strategic practices of HR, such as the competency management, still deserves attention of the academia through the accomplishment of deeper qualitative studies that exhibit not only interfering factors but also the initiatives that must be adopted by the organization to favor the implementation process.
Originality/value
The interventions occurred in an organization can or cannot stem from an articulated HR strategy. Some policies can be implemented without a previous explicit planning, and other planned strategies may never even be effectively implemented (Truss & Gratton, 1994). As reported by Kaufman (2015), some critical success factors to a large-scale organizational change – which is necessary for the effective adoption of strategic HR models – are the commitment of leaderships and a carefully planned and managed implementation. For such, it is necessary to manage programmed organizational changes properly and to act promptly on the cultural pressure perceived by all levels of the organization (Guest, 1987). Such premises are associated with the SHRM perspective proposed by Wright and Snell (1998), in which the authors claim that the main role of HR is to implement organizational strategies. Lengnick-Hall et al. (2009) present a research agenda that highlights the need to give more emphasis on issues related to the implementation of strategic human resource management, specifically regarding the vertical and horizontal alignment of HR systems.
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Luca Possidente, Nicola Tondini and Jean-Marc Battini
Buckling should be carefully considered in steel assemblies with members subjected to compressive stresses, such as bracing systems and truss structures, in which angles and…
Abstract
Purpose
Buckling should be carefully considered in steel assemblies with members subjected to compressive stresses, such as bracing systems and truss structures, in which angles and built-up steel sections are widely employed. These type of steel members are affected by torsional and flexural-torsional buckling, but the European (EN 1993-1-2) and the American (AISC 360-16) design norms do not explicitly treat these phenomena in fire situation. In this work, improved buckling curves based on the EN 1993-1-2 were extended by exploiting a previous work of the authors. Moreover, new buckling curves of AISC 360-16 were proposed.
Design/methodology/approach
The buckling curves provided in the norms and the proposed ones were compared with the results of numerical investigation. Compressed angles, tee and cruciform steel members at elevated temperature were studied. More than 41,000 GMNIA analyses were performed on profiles with different lengths with sections of class 1 to 3, and they were subjected to five uniform temperature distributions (400–800 C) and with three steel grades (S235, S275, S355).
Findings
It was observed that the actual buckling curves provide unconservative or overconservative predictions for various range of slenderness of practical interest. The proposed curves allow for safer and more accurate predictions, as confirmed by statistical investigation.
Originality/value
This paper provides new design buckling curves for torsional and flexural-torsional buckling at elevated temperature since there is a lack of studies in the field and the design standards do not appropriately consider these phenomena.
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Hüseyin Emre Ilgın, Markku Karjalainen and Sofie Pelsmakers
This study examined data from 13 international tall residential timber building case studies to increase our understanding of the emerging global trends.
Abstract
Purpose
This study examined data from 13 international tall residential timber building case studies to increase our understanding of the emerging global trends.
Design/methodology/approach
Data were collected through literature surveys and case studies to examine the architectural, structural and constructional points of view to contribute to knowledge about the increasing high-rise timber constructions globally.
Findings
The main findings of this study indicated that: (1) central cores were the most preferred type 10 of core arrangements; (2) frequent use of prismatic forms with rectilinear plans and regular extrusions were identified; (3) the floor-to-floor heights range between 2.81 and 3.30 m with an average of 3 m; (4) the dominance of massive timber use over hybrid construction was observed; (5) the most used structural system was the shear wall system; (6) generally, fire resistance in primary and secondary structural elements exceeded the minimum values specified in the building codes; (7) the reference sound insulation values used for airborne and impact sounds had an average of 50 and 56 dB, respectively.
Originality/value
There is no study in the literature that comprehensively examines the main architectural and structural design considerations of contemporary tall residential timber buildings.
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Abstract
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