scholarly journals Analysis of hygroscopic self-shaping wood at large scale for curved mass timber structures

2019 ◽  
Vol 5 (9) ◽  
pp. eaax1311 ◽  
Author(s):  
Philippe Grönquist ◽  
Dylan Wood ◽  
Mohammad M. Hassani ◽  
Falk K. Wittel ◽  
Achim Menges ◽  
...  

The growing timber manufacturing industry faces challenges due to increasing geometric complexity of architectural designs. Complex and structurally efficient curved geometries are nowadays easily designed but still involve intensive manufacturing and excessive machining. We propose an efficient form-giving mechanism for large-scale curved mass timber by using bilayered wood structures capable of self-shaping by moisture content changes. The challenge lies in the requirement of profound material knowledge for analysis and prediction of the deformation in function of setup and boundary conditions. Using time- and moisture-dependent mechanical simulations, we demonstrate the contributions of different wood-specific deformation mechanisms on the self-shaping of large-scale elements. Our results outline how to address problems such as shape prediction, sharp moisture gradients, and natural variability in material parameters in light of an efficient industrial manufacturing.

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1006
Author(s):  
Zhenhuan Chen ◽  
Hongge Zhu ◽  
Wencheng Zhao ◽  
Menghan Zhao ◽  
Yutong Zhang

China’s forest products manufacturing industry is experiencing the dual pressure of forest protection policies and wood scarcity and, therefore, it is of great significance to reveal the spatial agglomeration characteristics and evolution drivers of this industry to enhance its sustainable development. Based on the perspective of large-scale agglomeration in a continuous space, in this study, we used the spatial Gini coefficient and standard deviation ellipse method to investigate the spatial agglomeration degree and location distribution characteristics of China’s forest products manufacturing industry, and we used exploratory spatial data analysis to investigate its spatial agglomeration pattern. The results show that: (1) From 1988 to 2018, the degree of spatial agglomeration of China’s forest products manufacturing industry was relatively low, and the industry was characterized by a very pronounced imbalance in its spatial distribution. (2) The industry has a very clear core–periphery structure, the spatial distribution exhibits a “northeast-southwest” pattern, and the barycenter of the industrial distribution has tended to move south. (3) The industry mainly has a high–high and low–low spatial agglomeration pattern. The provinces with high–high agglomeration are few and concentrated in the southeast coastal area. (4) The spatial agglomeration and evolution characteristics of China’s forest products manufacturing industry may be simultaneously affected by forest protection policies, sources of raw materials, international trade and the degree of marketization. In the future, China’s forest products manufacturing industry should further increase the level of spatial agglomeration to fully realize the economies of scale.


Author(s):  
Alexander Miropolsky ◽  
Anath Fischer

The inspection of machined objects is one of the most important quality control tasks in the manufacturing industry. Contemporary scanning technologies have provided the impetus for the development of computational inspection methods, where the computer model of the manufactured object is reconstructed from the scan data, and then verified against its digital design model. Scan data, however, are typically very large scale (i.e., many points), unorganized, noisy, and incomplete. Therefore, reconstruction is problematic. To overcome the above problems the reconstruction methods may exploit diverse feature data, that is, diverse information about the properties of the scanned object. Based on this concept, the paper proposes a new method for denoising and reduction in scan data by extended geometric filter. The proposed method is applied directly on the scanned points and is automatic, fast, and straightforward to implement. The paper demonstrates the integration of the proposed method into the framework of the computational inspection process.


2016 ◽  
Vol 60 (2) ◽  
pp. 15-25
Author(s):  
V. Obolenskiy

The development of Russian foreign trade during the previous five years is analyzed. It is stated that, in terms of value, exports of services and imports of goods and services steadily grew during the first four years of the period under review. Exports of goods also rose during three years, but in 2014 both exports and imports again fell in comparison with the previous year as was the case five years ago. The composition of the Russian exports and imports of goods did not change radically during the previous years. The main items of export are, as always, mineral products, metals and fertilizers. Import is prevailed by foodstuffs, chemicals and heavy engineering equipment. The current situation is featured by the reduction of world oil prices, slump of the domestic economy and war of sanctions with the Western countries. All this substantially impairs the conditions of Russia’s foreign trade activities and inhibits its development in the upcoming years. In the author’s view, the implementation of measures worked out by the government – correction of tariff liabilities before the WTO, redirecting of trade streams from the European to the Asian markets, import substitution and export support – will unlikely improve the situation. Revision of the liabilities before the WTO in the conditions of the decrease of the internal demand and serious devaluation of Ruble is considered as inappropriate and counterproductive. “Asiatic turn” is only capable to compensate to a certain respect the loss of supplies of some food products from Europe, but cannot fully offset the loss of potentialities of the acquisition of modern technologies and equipment from the developed countries. It is doubtful that it will be possible to dramatically cut the import dependence. It is necessary to replace many kinds of foreign goods, but it is impossible to implement a frontal substitution of import in all directions. Excessive stress on the import substitution might lead to the emergence of shortages and poorer availability of some goods at the internal market and, at the worst, to self-isolation and economic autarky. The attempts to build up an effective system of export support might be successful only in the conditions of the establishment of the large-scale production of goods and services which would be comparable with the foreign analogues in respect to the criteria of price and quality. Taking this into consideration the technological renovation of production processes, first of all in the manufacturing industry, and on this basis rising up of the competitiveness of plants and factories are the most important prerequisites for encouraging export activities and formation of the new export specialization of the country.


2021 ◽  
pp. 103731
Author(s):  
Samuel Ayanleye ◽  
Kenneth Udele ◽  
Vahid Nasir ◽  
Xuefeng Zhang ◽  
Holger Militz

Author(s):  
Tim Gleason ◽  
Gordana Herning ◽  
John Klein

<p>This paper investigates the design of lateral force resisting systems (LFRS) for multi-story mass timber structures in Boston, MA. Structural and environmental tradeoffs of replacing conventional concrete cores or steel braced frames with glue-laminated timber (GLT) braced frames are evaluated through numerical analyses of 8-, 12-, and 18-story building prototypes. Finding an optimal timber gravity system configuration is followed by examining lateral resistance of the prototypes. The resulting designs demonstrate a practical approach to assist designers in selecting a lateral system during the early stages of conceptual design. This research was conducted in parallel with a related study for implementation of mass timber in affordable housing in Boston, enabling a comparison between composite systems and all-timber structures.</p>


2017 ◽  
Vol 1 (1-4) ◽  
pp. 49-60 ◽  
Author(s):  
Philipp Eversmann ◽  
Fabio Gramazio ◽  
Matthias Kohler

2013 ◽  
Vol 315 ◽  
pp. 472-476
Author(s):  
Adnan Hj. Bakri ◽  
Abdul Rahman Abdul Rahim ◽  
Noordin Mohd Yusof

The objective of this short review paper is to examine the practical applications of Total Productive Maintenance (TPM) in the manufacturing industry. In this short review, an attempt was made to critically discuss the previous literatures related to TPM with the other established quality initiatives in the manufacturing, such as Total Quality Management (TQM) and Just-In-Time practice (JIT). This literature review-based research revealed an important research gaps related to TPM. The significance role of TPM as an important complementary to either TQM or JIT initiative is observed not been well addressed in the available literatures. Most of the researches available investigate these initiatives separately, focuses on the other element rather than addressing on the significant role of TPM as one of the main thrust. The separate implementation of such quality initiatives in the manufacturing organization means the requirement of large scale human, financial and technical resources as well the associated problems of running competing project in the company. The outcomes from this review justify the needs of further research in the area of TPM integration with other available initiatives, to further enhance its methodology aimed at solidifying its philosophy towards more realistic practical applications.


2018 ◽  
Vol 7 (3.1) ◽  
pp. 9
Author(s):  
Geevarghese . ◽  
R J.T Nirmalraj ◽  
Hemalatha Seeram ◽  
S Veena ◽  
Beena James

The nature of human resources and their willingness to contribute have an impact on the existence and growth of the organization. Employee loyalty may be defined as employees being committed to the success and growth of the organization and believing that working for this organization is their obligation and best option available to them. The growth and success of organizations in the present scenario, largely depends upon the commitment and loyalty of its workforce. As employees work for the organizations for certain period of time, they develop affinity and emotional attachment to the organization. As they grow older their maturity level will increase and stop job hopping. Further, as the age of the employee increases, they will try to settle down in one place and the probability of their intention to stay with the organization also will increase which in turn will influence their loyalty to the organization.  Therefore, age of an employee is generally considered as a factor influencing loyalty to the organization.The purpose of this paper is to investigate the effect of age of employee on employees’ loyalty in a Bangalore based large scale public sector undertaking. 200 middle level executives who have completed minimum of one year service were surveyed and random sampling technique was adopted. Survey was conducted with a standardized, valid and reliable instrument measuring loyalty. The detailed findings and implications are discussed in the full paper.  


2021 ◽  
Author(s):  
◽  
Gabriella Joyce

<p>In a climate where standard methods of construction are being challenged, developments in engineered timbers are allowing mass timber construction to be explored as a sustainable alternative to traditional building methods. Cross- laminated timber (CLT) is at the forefront of this evolution and, with the advancement in computational design and digital fabrication tools, there lies an opportunity to redefine standard construction. This project explores how digital modelling and advance digital fabrication can be combined to generate a connection system for CLT panels.  The advantages of CLT and mass timber construction are numerous and range from environmental and aesthetic benefits to site safety and cost reduction benefits. There are, however, issues that remain surrounding the connections between CLT panels. Steurer (2006, p.136) stated that, “Progress in engineered timber construction is directly related to developments in connector technology.” This thesis creates connections inspired by traditional Japanese joinery that have been adapted to be used for the panel construction of CLT structures. Using CLT offcuts as a primary connection material, the system not only reduces waste but also mitigates thermal bridging and lowers the number of connection points whilst increasing the ease of building and fabrication.  The connections are first considered at a detail scale. They use the literature review and case studies as a base for design before being tested using digitally fabricated prototypes. These prototypes are evaluated against a framework created in line with the aforementioned criteria. Within this framework, the connections are analysed against existing connection systems as well as previous designs to establish a successful system. The connections are then evaluated within the context of a building scale and considers large-scale fabrication and on- site assembly whilst continuing to focus on the reduction of waste. This research found that the simplicity of the connections is key to a successful system as this allows for faster and cheaper fabrication and installation. However, there is still further research needed surrounding large-scale fabrication and the structural capacity of timber connection systems.</p>


Holzforschung ◽  
2018 ◽  
Vol 72 (10) ◽  
pp. 871-879 ◽  
Author(s):  
Daniel F. Llana ◽  
Guillermo Íñiguez-González ◽  
Joaquín Montón ◽  
Francisco Arriaga

AbstractNeedle penetration resistance (NPR), screw withdrawal resistance (SWR), core drilling (CD) and drilling chips extraction (DCE) are nondestructive and semi-destructive techniques used to estimate density in timber structures. In most of the previous studies, these techniques were tested in clear sawn timber and clear specimens. The goal of the present paper is to study the relationship between density and these techniques by means of five different devices in whole pieces of timber from built-in engineering structures, which are from 12 4.5-m long structural timber joists of Norway spruce from a 19thcentury building in Barcelona (Catalonia, Spain). Although determination coefficients (R2) for density estimation models were lower than those from clear timber, the results obtained confirmed that these four techniques are suitable forin-situdensity estimation of woods in buildings. The best results were obtained by CD (the bigger the bit, the higher the correlation), followed by DCE, and SWR. The worst correlation was found for NPR devices, but the results could be probably improved with more measurements.


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