Load-Carrying Efficiency of Homogeneous Wood Composites

Load-carrying efficiency is defined here on the basis of load-carrying capacity of a composite board per unit weight. Relationships are derived for evaluating the load-carrying efficiency for tension, compression, shear, and bending applications. As an illustration of the application of the theory, limited experimental data are provided for both particleboard and fiberboard to illustrate that optimum load-carrying efficiency does not necessarily occur at the highest density at which these composites can be manufactured. Further, it is shown that optimum load-carrying efficiency varies for different products and load types. These optimum points may not occur at the highest strength and stiffness values attainable for these products

Legal Doctrinal Scholarship and Interdisciplinary Engagement

The paper offers a legal theoretical analysis of the disciplinary character of the contemporary practice of legal scholarship. It is assumed that the challenges of interdisciplinary engagement are particularly revealing about the nature of legal scholarship. The paper argues for an understanding of legal scholarship that revolves around cultivating doctrinal knowledge about law. Legal scholarship is characterised as a normative and interpretive discipline that offers an internalist and non-instrumentalist perspective on law. The paper also argues that interdisciplinary engagement is sometimes necessary for legal scholars because some concepts and ideas built into the doctrinal structures of law cannot be made fully intelligible by way of pure normative legal analysis. This point is developed with the help of an epistemological clarification of doctrinal knowledge and anchored in an account of the practice of legal scholarship. The paper explores the implications of this account by way of analysing three paradigms of interdisciplinary engagement that respond to distinctive challenges facing legal scholarship: (1) understanding better the extra-legal origins of legal ideas, (2) managing discursive encounters that can generate frictions between disciplinary perspectives, and (3) building the knowledge base to handle challenge of validating policy initiatives that aim at changing the law. In different ways, all three challenges may require legal scholars to build competence in other disciplines. The third paradigm has particular relevance for understanding the methodological profile of legal scholarship. Legal scholarship is the only discipline with specific focus on how the social environment affects the doctrinal structures of law

Investigating the foreign language effect as a mitigating influence on the ‘optimality bias’ in moral judgements

Bilinguals often display reduced emotional resonance their second language (L2) and therefore tend to be less prone to decision-making biases in their L2 (e.g., Costa et al. in Cognition 130(2):236–254, 2014a, PLoS One 9(4):1–7, 2014b)—a phenomenon coined Foreign Language Effect (FLE). The present pre-registered experiments investigated whether FLE can mitigate a special case of cognitive bias, called optimality bias, which occurs when observers erroneously blame actors for making “suboptimal” choices, even when there was not sufficient information available for the actor to identify the best choice (De Freitas and Johnson in J Exp Soc Psychol 79:149–163, 2018. https://doi.org/10.1016/j.jesp.2018.07.011). In Experiment 1, L1 English speakers (N = 63) were compared to L2 English speakers from various L1 backgrounds (N = 56). In Experiment 2, we compared Finnish bilinguals completing the study in either Finnish (L1, N = 103) or English (L2, N = 108). Participants read a vignette describing the same tragic outcome resulting from either an optimal or suboptimal choice made by a hypothetical actor with insufficient knowledge. Their blame attributions were measured using a 4-item scale. A strong optimality bias was observed; participants assigned significantly more blame in the suboptimal choice conditions, despite being told that the actor did not know which choice was best. However, no clear interaction with language was found. In Experiment 1, bilinguals gave reliably higher blame scores than natives. In Experiment 2, no clear influence of target language was found, but the results suggested that the FLE is actually more detrimental than helpful in the domain of blame attribution. Future research should investigate the benefits of emotional involvement in blame attribution, including factors such as empathy and perspective-taking

Nondestructive evaluation of wood properties by stress wave spectral analysis

The influence of selected properties on the propagation of stress waves in wood was investigated. Waveform analysis of the stress waves was performed using spectral analysis techhniques developed for stationary random processes. Information analyzed from the stress waves included wave velocity, energy spectra, and the frequency response function. Three wood properties investigated as to their influence on stress waves propagation were grain angle, moisture content, and weight loss caused by decay. Significant relationships between grain angle and the wave properties of velocity, amplitude gain, and total gain were obtained. Significant damping of the stress waves was observed at large grain angles and moisture content values above the fiber saturation point. No significant equations were found for consistent prediction of moisture content. The results of the decay study showed that as weight loss increased, the ratio of energy of the stress wave to that input to the specimen decreased for the perpendicular to grain case. Two approaches toward prediction of wood strength were investigated. The first method employed prediction of wood properties from the stress wave spectral characteristics. Known relationships between these wood properties and strength were then utilized. The second approach involved direct correlation of the stress wave spectral properties with strength. Significant correlatlons with strength were obtained using both approaches. Application of basic results are discussed as to their applicability toward development of an [sic] nondestructive evaluatlon (NOE) procedure for wood poles used in transmission line structures

Stacking Characteristics of Composite Cardboard Boxes

This paper presents a simplified model and method for finding the deflection char acteristics of stacked cardboard boxes, provided the load-deflection characteristic of the box is known. A computer program, based on this model, allows the stability of stacked boxes to be investigated and to indicate the limits to the height of the stack and box parameters required to prevent stack toppling.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68424/2/10.1177_073168448300200302.pd

Chestnut wood in compression perpendicular to the grain : non-destructive correlations for test results in new and old wood

This paper addresses the evaluation of the compressive properties of chestnut wood under compression perpendicular to the grain, using destructive and non-destructive methods. Three non-destructive methods (ultrasonic testing, Resistograph and Pilodyn) are proposed and the possibility of their application is discussed based on the application of simple linear regression models. Timber specimens were tested up to failure, divided in two different groups for assessing a possible load history related degradation, namely New Chestnut Wood (NCW), never been used structurally, and Old Chestnut Wood (OCW), obtained from structural elements belonging to ancient buildings. The specimens were also divided into four groups according to the orientation of annual growth rings towards load and wave propagation direction. The results show, in general, good correlations between compression strength and stiffness with non-destructive techniques via ultrasonic testing, Resistograph and Pilodyn. However, the orientation of the loading direction with respect to the annual growth rings must be taken into account. This conclusion, and the observation that NCW and OCW shows correlations and regression models usually different, add additional complexity to the quantitative use of non-destructive evaluation techniques for the assessment of the mechanical behaviour of timber elements.Fundação para a Ciência e Tecnologia (FCT) - SFRH/BD/ 5002/200

Material variability and wood joist floor response

CER75-76RVG-MEC-JRG-MDV-JB46.May 1976.Includes bibliographical references

Layered beam systems with interlayer slip

CER72-73MFK-JRG-MDV-MEC-JB27.December, 1972.Includes bibliographical references (pages 118-120).This report describes a portion of a study on wood joist floor systems. The objective of this portion of the study is to develop a general theory for the analysis of the layered beams within the system including the effects of interlayer slip. The development leads to the governing equations for beams having a single axis of symmetry and an arbitrary number of layers and fastened together with mechanical connectors. Solutions to the governing equations are presented in closed form and in finite difference approximation. These solutions show the effect of interlayer connection on the deflection. In all cases, consideration is given to variation of properties along the beam length. The results of some tests are presented. The proposed theory is shown to agree favorably with the results obtained in the tests

Verification of a mathematical model for layered T-beams

CER73-74MLK-MEC-JRG-JB-EGT-MDV28.March 1974.Includes bibliographical references.An experimental program and the verification of a mathematical model for layered T-beams, developed assuming small deflection theory and including effects of interlayer slip, are described in this report. This research is a part of an overall program to develop a verified analysis procedure for wood joist floor systems. After a description of the construction and load-testing of 14 two-and three-layered T-beams, a brief discussion on the mechanical properties of the materials used is given. The deflections observed in the loading tests are then compared with the predicted deflections given by the mathematical model, which used a finite element solution technique. These comparisons for the fourteen T-beams, including two and three-layered systems, formed the primary basis for the verification of the mathematical model. Test results provided by a manufacturer of joist systems were also compared to the mathematical model. Good agreement between the observed and theoretical values were obtained for all tests. These favorable results show the validity of this general layered beam theory

Finite element modelling of moisture related and visco-elastic deformations in inhomogeneous timber beams

Wood is a hygro-mechanical, non-isotropic and inhomogeneous material concerning both modulus of elasticity (MOE) and shrinkage properties. In stress calculations associated with ordinary timber design, these matters are often not dealt with properly. The main reason for this is that stress distributions in inhomogeneous glued laminated members (glulam) and in composite beams exposed to combined mechanical action and variable climate conditions are extremely difficult to predict by hand. Several experimental studies of Norway spruce have shown that the longitudinal modulus of elasticity and the longitudinal shrinkage coefficient vary considerably from pith to bark. The question is how much these variations affect the stress distribution in wooden structures exposed to variable moisture climate. The paper presents a finite element implementation of a beam element with the aim of studying how wooden composites behave during both mechanical and environmental load action. The beam element is exposed to both axial and lateral deformation. The material model employed concerns the elastic, shrinkage, mechano-sorption and visco-elastic behaviour of the wood material. It is used here to simulate the behaviour of several simply-supported and continuous composite beams subjected to both mechanical and environmental loading to illustrate the advantages this can provide. The results indicate clearly both the inhomogeneity of the material and the variable moisture action occurring to have had a significant effect on the stress distribution within the cross-section of the products that were studie