scholarly journals Characterization and Structural Performance in Bending of CLT Panels Made from Small-Diameter Logs of Loblolly/Slash Pine

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2436 ◽  
Author(s):  
Vanesa Baño ◽  
Daniel Godoy ◽  
Diego Figueredo ◽  
Abel Vega
Keyword(s):  
Bending Strength ◽  
Strength Class ◽  
Small Diameter ◽  
Slash Pine ◽  
Structural Performance ◽  
Visual Grade ◽  
Cross Laminated Timber ◽  
Thinning Operations ◽  
Sawn Timber ◽  
The Individual

The main objective of this work was to study the structural viability of using small-diameter logs of Uruguayan Loblolly/Slash pine, mainly from thinning operations, to design cross-laminated timber (CLT) panels. A visual grade named “CTH” (coniferous thinning) was proposed, and 45 specimens of sawn timber boards were tested, resulting in 51% lower bending strength than that of the minimum strength class C14. Subsequently, 20 CLT panels were manufactured and experimentally tested, the results showed that the bending strength of the CLT panels was 43% above that of the individual layers. Additionally, the structural performance of the CLT panels for use in floors was calculated, and the thickness-span relationship depending on strength class and imposed load are presented. Results showed than the use of CTH timber to design CLT floors implies a volume (m3/m2) 17% higher than that using C24 timber.

scholarly journals Efficiency of Visual and Machine Strength Grading of Sawn Timber with Respect to Log Type

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1467
Author(s):  
Izabela Burawska-Kupniewska ◽  
Sławomir Krzosek ◽  
Piotr Mańkowski
Keyword(s):  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Strength Class ◽  
Limited Extent ◽  
Visual Method ◽  
Medium Quality ◽  
Sawn Timber ◽  
Machine Strength

A batch of pine timber sawn from butt, middle and top logs was strength graded with the visual method (classification into grading classes KW—best quality, KS—medium quality, KG—inferior quality and Reject) and with the machine strength grading method—performed with the use of a mobile timber grader (classification into C strength classes). We compared the efficiency of grading classes and strength classes, depending on the type of log from which the material was obtained (butt, middle, top). Next, a strength grading machine was used to measure the modulus of elasticity in bending (MOE) and static bending strength (MOR). The ANOVA confirmed the influence of both the log type (butt, middle, top), the C strength class, and the visual strength grading class on the values of density (DEN) and MOR. Timber density and MOR decreased from the butt log section to the top log section. The ANOVA confirmed the influence of log type on MOE values, but only to a limited extent.

Feasibility of manufacturing cross-laminated timber using fast-grown small diameter eucalyptus lumbers

2017 ◽  
Vol 132 ◽  
pp. 508-515 ◽  
Author(s):  
Yuchao Liao ◽  
Dengyun Tu ◽  
Jianhui Zhou ◽  
Haibin Zhou ◽  
Hong Yun ◽  
...  
Keyword(s):  
Small Diameter ◽  
Cross Laminated Timber

scholarly journals RESULTS OF TESTING OF MODERN INDIVIDUAL MILKING INSTALLATION

2021 ◽  
Author(s):  
O. Kryshtal ◽  
Keyword(s):  
Technological Process ◽  
Mass Fraction ◽  
Total Duration ◽  
Small Diameter ◽  
First Grade ◽  
Vacuum Pump ◽  
Average Intensity ◽  
Milking Machine ◽  
The Individual

The purpose of the research: comprehensive assessment of the individual milking unit of the company "Kurtsan" (Turkey) during operation. Methods of research: Analysis of the structural features of the individual milking unit performed by the observation method given to test sample, the quality of the machine was evaluated by standardized methods: the quality of the technological process and operational-technological indicators in accordance with the SOU 74.3-37-273, energy indices according to DSTU 2331, economic Indicators according to DSTU 4397, safety indicators and ergonomics according to DSTU IEES 60335-1, DSTU EN 60335-2-70. Research Results: The conducted research confirms a sufficiently high quality of the technological process of selection of milk in cows in the conditions of use of milking installation in a personal economy, which provides favorable conditions for the milking of the cow, taking into account its physiological features. Performance per hour of basic time is 10 heads. Milking installation works on the principle of a closed milking system, thanks to which milk does not contact the environment and immediately from the basin enters a sealed can. Such system protects milk from the possibility of bacterial and physical contamination. Milk obtained during milking by milking installation according to quality indicators (acidity, density, content of somatic cells, mass fraction of dry matter, mass fraction of fat) meets the requirements for the first grade according to DSTU 3662. Milking installation is equipped with a dry vacuum pump. Power consumption during installation does not exceed 0.54 kW. Specific electricity consumption for milking of one cow is 0.05 kWh / head. Annual operating expenses for milking of two cows in the farm are 1591.90 UAH / head. Conclusions. According to the testing of the individual milking plant manufacturing company "KURTSAN", it has been established that this installation reliably performs the technological process of machine milking of cows in milking can for their tethered maintenance and allows you to get milk of the first grade. The total duration of visiting one cow is 5.75 minutes. The average intensity of milk is 1.0 kg / min. Milking machine provides complete bodies of cows. The magnitude of the control manual feed is 50 ml. The milking machine is equipped with an adjustable pulsator of pairwise milking, which creates a manual milking process and works for a working vacuum of 40 ± 1 kPa, which prevents injury to dies and diseases of mastitis. In the cover the "Stop-Milk" system is installed, which prevents milk from entering a vacuum pump during the overflow of the poor, or water while washing All items are compactly assembled on a single cart. However, a small diameter of wheels on an unequal surface creates some inconvenience to the operator during the transportation of the machine with a filled milk capacity. The application of the installation increases the amount of milk received. Its gentle work does not harm the emotional and physical health of the cow: the dysfunctions during operation are not pushed, and light vibration creates a massage effect. Milking installation allows you to significantly reduce the labor of service personnel in an economy with a maintenance of 1 to 10 cows.

Characterizing Canopy Fuels to Predict Fire Behavior in Pitch Pine Stands

2007 ◽  
Vol 24 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Matthew J. Duveneck ◽  
William A. Patterson
Keyword(s):  
Fire Behavior ◽  
Small Diameter ◽  
Basal Area ◽  
Regression Equations ◽  
Crown Fire ◽  
Pinus Rigida ◽  
Canopy Fuels ◽  
Pitch Pine ◽  
Thinning Operations ◽  
Pine Stands

Abstract Destructive sampling of 31 pitch pine (Pinus rigida P. Mill) trees ranging in dbh from 2.7 to 42.5 cm and in height from 4.1 to 23.8 m provided a complete inventory of needles and small-diameter branch weights used to characterize canopy fuels to predict fire behavior in pitch pine stands. Regression equations using dbh as an independent variable predict canopy bulk density with an r2 > 0.93. The results provide managers with a method of evaluating the effectiveness of thinning operations in reducing crown fire potential in well-stocked stands. To demonstrate the application of the method, we calculated the wind speed (Crowning Index [CI]) needed to sustain an active crown fire in thinned and unthinned pitch pine stands in Montague, Massachusetts. Thinning to 2.8 m2/ha basal area increased the CI from 34 to 98 km/hour.

The Impact of Varying Feature Dimensions on Substrate Reliability Risks

2005 ◽  
Author(s):  
Kayleen L. E. Helms ◽  
Qing A. Zhou ◽  
Charles Zhang
Keyword(s):  
Individual Component ◽  
Sensitivity Study ◽  
Design Guidelines ◽  
Structural Performance ◽  
Local Geometry ◽  
Thermomechanical Loading ◽  
Future Design ◽  
Linear Material ◽  
The Individual ◽  
The Impact

A sensitivity study is undertaken to characterize the impact of varying feature dimensions in emerging electronic packaging technologies. Specifically, the overall structural performance of the substrate under use conditions (thermal and combined thermomechanical loading) is investigated. The study consists of both modeling and experimental efforts. Modeling approaches are employed within the framework of a finite element code to simulate performance of different design geometry combinations in the known failure mode of solder resist layer cracking. In the models, two levels of complexity are used to better identify the impact of the individual features on the overall substrate reliability. First, local geometry is captured by including each substrate layer. Individual component geometries like microvias and PTHS are also explicitly modeled to capture synergistic failures modes. Second, more realistic non-linear material properties are used to characterize time, temperature, and rate-dependant constitutive behavior of individual substrate materials such as buildup, core, metal, etc. In the experiments, substrate warpage and reliability data is collected for validating the predictive modeling capability. From this study, directions for future design guidelines varying feature dimensions while maintaining substrate reliability are proposed.

Evaluating timber quality in larger-diameter standing trees: rethinking the use of acoustic velocity

Holzforschung ◽  
2019 ◽  
Vol 73 (9) ◽  
pp. 797-806 ◽  
Author(s):  
Luka Krajnc ◽  
Niall Farrelly ◽  
Annette M. Harte
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Small Diameter ◽  
Longitudinal Direction ◽  
High Ratio ◽  
Acoustic Velocity ◽  
Timber Quality ◽  
Standing Trees ◽  
The Mean ◽  
Acoustic Velocities

AbstractThe use of acoustic velocity for different purposes is becoming widespread in the forestry industry. However, there are conflicting reports on how well this technology reflects the mechanical properties of trees. In this study, the prediction of timber quality using acoustic technology was evaluated on mature standing trees of three softwood species. The velocity in 490 standing trees was measured in several directions (longitudinal, radial and tangential). A sub-sample of trees was felled and the acoustic velocity was measured in 120 logs which were then sawn into structural-sized timber. A total of 1383 boards were tested for bending, as were small clear specimens extracted from the structural-sized boards. The mean tree values of the timber grade-determining properties (elastic modulus, bending strength and density) of both specimen sizes were related to the acoustic velocities and tree slenderness. The correlations between the mean tree mechanical properties and acoustic velocities were relatively low, most likely due to a high ratio of diameter to measurement distance. The transverse directions showed similar correlations with mechanical properties in larger-diameter trees to the longitudinal direction, as did tree slenderness. The results suggest that while the acoustic velocity in the longitudinal direction can reflect the mean tree mechanical properties in small-diameter trees, alternatives are needed to achieve the same in larger-diameter trees.

Limit Load Interaction of Welded Piping Branch Junctions Subjected to Combined Internal Pressure and Bending

2005 ◽  
Vol 297-300 ◽  
pp. 685-690 ◽  
Author(s):  
Fu Zhen Xuan ◽  
Pei Ning Li ◽  
Shan Tung Tu
Keyword(s):  
Parabolic Equation ◽  
Internal Pressure ◽  
Small Diameter ◽  
Limit Load ◽  
Fe Analysis ◽  
Diameter Ratio ◽  
Linear Finite Element ◽  
The Individual ◽  
Linear Expression ◽  
Parameter Influence

Systematic detailed non-linear finite element (FE) analysis are described for limit load interaction of piping branch junctions subjected to internal pressure and bending. The results show that for the tees with a small diameter ratio, the limit load interaction closes to the linear expression; as diameter ratio d/D increasing, the interaction relationship tends to parabolic equation; for the piping branch junction with diameter ratio equaling to unit, the limit load combinations is approximately quadratic. Compared to the individual limit bending value, internal pressure slightly increases the bending capability as it is in the range of 0.2£P/PL£0.4, especially for the cases of the main pipe with thinner wall. A closed limit load solution is obtained from the FE results through accommodating the geometrical parameter influence, and validated by using experimental results.

CATPUAL - An Innovative and High-Performance Hybrid Laminate with Carbon Fibre-Reinforced Thermoplastic Polyurethane

2017 ◽  
Vol 742 ◽  
pp. 294-301 ◽  
Author(s):  
Camilo Zopp ◽  
Daisy Nestler ◽  
Jürgen Tröltzsch ◽  
Maik Trautmann ◽  
Sebastian Nendel ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
High Performance ◽  
Bending Strength ◽  
Thermoplastic Polyurethane ◽  
Structural Diversity ◽  
Thermoplastic Matrix ◽  
Hybrid Laminates ◽  
Interlaminar Shear ◽  
The Individual ◽  
Hybrid Laminate

In consideration of environmental aspects and limited availability of resources, the focus of automotive and aerospace industry lies on significant weight optimisations especially for moving loads. In this context, innovative lightweight materials as well as material combinations need to be developed. A considerable potential for lightweight structures can be found in fibre- or textile-reinforced semi-finished products. Due to their specific characteristics and extraordinary structural diversity, thermoset and thermoplastic matrix systems can be used. In particular, carbon fibres as reinforcing components combined with a thermoplastic matrix polymer are able to create new high-performance applications. Besides the significant lightweight characteristics of the fibre-plastic-composites, in some instances contrary requirements must be satisfied in many areas, such as strength and ductility. In this field, the combination of fibre-reinforced polymers with aluminium or titanium sheets creates unique composite materials, so called hybrid laminates, which fulfil the unusual expectations.The focus of the current study lies on the development of a new thermoplastic hybrid laminate named CATPUAL (CArbon fibre-reinforced Thermoplastic PolyUrethane/ALuminium laminate). The structure of the laminate is an alternating sequence of thin aluminium sheets (EN AW 6082-T4) and fibre-reinforced thermoplastic polyurethane (TPU). The individual layers are consolidated to each other by using a hot pressing process. First results showed that the impregnation capability of thermoplastic polyurethane surpasses any other commercially available hybrid laminates. Furthermore, the mechanical properties regarding bending strength and interlaminar shear strength are exceeding the state of the art drastically.

scholarly journals Structural Performance Analysis of Cross Laminated Timber (CLT) Produced From Pine and Spruce Grown in Turkey

2020 ◽  
Vol 5 (5) ◽  
pp. 819-824
Author(s):  
Abdullah Uğur BİRİNCİ ◽  
Hasan ÖZTÜRK ◽  
Cenk DEMİRKIR ◽  
Gürsel ÇOLAKOĞLU
Keyword(s):  
Performance Analysis ◽  
Structural Performance ◽  
Cross Laminated Timber
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