The role of flute morphology in mechanical behaviour of corrugated fibreboard : a numerical, analytical and empirical study : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering at Massey University, Palmerston North, New Zealand

Corrugated fibreboard (CFB) packaging is designed to protect its contents during the shipping and storage of goods – a role threatened by damage to the CFB. Damaged goods will not only make the customers unhappy but also cause significant loss to the suppliers. As different goods require different design of CFB box, there is no one solution fits all to overcome this issue. This thesis was focused on understanding the fundamentals of CFB damage, relating the damage with the strength loss, and including the damage in strength predictive tools such as finite element (FE) and analytical models to allow for faster design of CFB boxes and the possibility of finding optimal solutions for different requirements. The type of CFB damage that the research narrowed down into was changes to the flute profile that could arise. Such flute damage could be unintentional (crushing and indentation at any stage during the shelf life of the packaging) or intentional (accompanying perforation for instance – a design option to provide secondary functionality such as in shelf ready applications). There is currently no systematic way of observing and quantifying the structure of the flute profile to allow for a proper understanding of the morphology of the flute. Typically, this is done either through measuring the change in calliper or direct observation on the profiles at the edge of CFB blanks which suffers additional physical damage due indentation from the cutting process. A new technique was presented to be able to do this by laser cutting the samples and digitalising the flutes. The method also includes a statistical tool that can compare different flutes and quantify the change in morphology through a variable called the ‘Similarity Factor’. The technique was demonstrated for flute profiles with different extents of crushing, and also allowed for transferring the digitalised profile for FE modelling purposes. Developing a full box compression strength (BCT) FE model with the micro-geometry of the fluting structure can be very time consuming as it will involve a huge number of mesh element and result in a long simulation time. So to overcome this, smaller component models like the bending and crushing tests that have been shown to be the largest factor affecting the BCT were developed with micro-geometry structure that allowed for significantly less computation time and better understanding of the effect of flute profile. A new finding identified through the application of the bending model was that the orientation of the sample can be rotated to find an optimal orientation angle that gives the best bending stiffness and maximum bending force performance. Analytical models were also assembled, and their performance compared with the FE models. These provided accurate outcomes for bending but were limited in cases such as inability to predict the maximum bending force and determining the locus of failure. Global damage to the CFB was simulated through deliberately crushing samples to different extents experimentally. The effect of different levels of crushing on flute morphology and mechanical performance was measured through image analysis, torsional, compressive and bending tests. These tests showed that the torsional behaviour of CFB had the highest sensitivity to crushing at low levels. Since the flute morphology measurements showed negligible changes (the original flute geometry was recovered after crushing), it is suggested that the crushing could affect other localised damage to CFB components such as to the fibres in the constituent papers. Further investigation of the extent and nature of this damage could be an interesting extension to find out its relation to the BCT. On the other hand, the reduction in bending strength and edge crush test followed a similar tend to change in flute morphology with increasing crush levels. This shows that some of the loss in strength could be attributed to the change in flute geometry as well as the reduction in calliper (beyond a threshold where morphology was recoverable after compression). By combining the new tool to characterise the flute structure and with models of varying complexity, their ability to predict the strength of CFB at different extents of crushing could be compared (simulating unintentional damage). These models consisted of an actual flute geometry, idealized flute geometry and an equivalent flute geometry FE models along with analytical solution models. This comparison showed that the use of an actual flute geometry was useful to predict mechanical performance but that the dominant effect on bending strength is the calliper and the flute morphology is a secondary influence. The utility of the FE model was further demonstrated with inclusion of an intentional localised damage through perforation. The model accurately predicted the drop in the experimentally measured apparent bending stiffness. The findings of the localised perforation study also demonstrated that the bending force of the CFB can be significantly improved by avoiding punching through the peaks that rest on the compressive side of the liner. The key new contribution of this research was the development of new a way to accurately measure and describe the actual flute profile within CFB exposed to pre-test damage. The profile allowed geometric damage to be quantified and for the true profile to be included in detailed finite element modelling of mechanical behavior. The effect of flute damage on the mechanical behavior of CFB could therefore be determined and predicted and allowed the potential effects on the strength of CFB packages to be inferred

Advanced Eco-friendly Wood-Based Composites

In collaboration with the MDPI publishing house, we are pleased to introduce the reader to our new project, a Special Issue entitled “Advanced Eco-friendly Wood-Based Composites”. This Special Issue provides an opportunity to investigate advanced eco-friendly wood-based composites from a broader perspective. The coronavirus pandemic and shutdown measures employed to contain it, as well as the ongoing war in Ukraine, have influenced and decelerated the world economy and adversely impacted research activities on most levels in all countries. Surprisingly, researchers in the field of wood-based composites have continued to make progress, which is also described in this Special Issue

Index to 1981 NASA Tech Briefs, volume 6, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1981 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Design of a Variable Camber Flap for Air Cargo Challenge Aircraft

The need for a more competitive Air cargo challenge (ACC) aircraft led the pursuit for a more aerodynamic efficient wing. This work details the various steps taken in the design of a gapless flap system with the actuation mechanism inside for a clean surface. Multiple flexible joint specimens designs were manufactured and tested with the help of a special constructed test bench to assert the required torque to bend certain degrees. The goal is to serve as a flexible skin in the flap hinge line. A system that rotates around an axis on the lower wing skin means that the upper skin changes in length, arising the need for a flexible material. A RTV silicone rubber was chosen to close the upper surface flap gap. A novel test apparatus was devised to determine the silicone Young’s Modulus and Poisson’s ratio so the sheet could be sized. An adhesion test was also performed using a suitable bonding agent to verify if it had the capability of performing the task at hand. The full range of hinge acting moments was determined. Aerodynamic hinge moment was simulated with XFOIL software, while the elastomer’s was calculated with the found properties and trigonometry. Due to the elastomeric nature of silicone, air pressure effects were evaluated using XFOIL Cp curves to calculate resulting loads and a subsequent FEM analyse with Ansys Mechanical module predicted the outer plane deformations. A program in Matlab was written to help dimension the actuation system. Optimization was achieved by comparing the servo motor available hinge torque with the resisting moments sum (aerodynamic, elastomer and flexible skin joint). With all the described methodology, a final design was purposed based on the central wing panel of ACC 2019 edition model. To not only validate the concept at hand but also the employed methodology, a small (250 mm span) section was manufactured using conventional 2 parts hollow moulded manufacturing process. For the novel concept, a silicone sheet bonding procedure was planned and required a special mould for the effect. After de­moulded, the section was trimmed and the servo motor was installed to check the concept functionality. A final experiment using a modified bench test was realized to compare the projected hinge moments with the built section one’s.A necessidade de uma aeronave mais competitiva para as edições do Air Cargo Challenge levou à procura de uma asa mais eficiente aerodinamicamente. Esta dissertação descreve os varios passos que levaram ao desenho de um flap sem fenda, com o mecanismo de atuação imbutido, para garantir uma superficie limpa. Multiplos espécimes com junta flexível foram produzidos e testados com recurso a uma bancada de testes construída para o efeito, de forma a calcular­se o binário necessário para determinada deflexão. As juntas têm o objetivo de servirem como cascas flexíveis na dobradiça do flap. Um dispositivo que revolve em torno de um eixo localizado no intradorso faz com que a casca do extradorso altere em comprimento, surgindo a necessidade de um material elástico. Um silicone RTV foi escolhido para fechar a fenda do flap. Um novo método experimetal foi pensado para determinar o módulo de Young e o coeficiente de Poisson de forma a dimensionar a folha de silicone. Um teste foi realizado para aferir a capacidade de adesão de um agente selante. A totalidade dos momentos que actuam sobre a dobradiça foram calculados. O momento aerodinâmico foi determinado com o recurso ao programa XFOIL, enquanto o do elastômero foi calculado com base nas suas propriedades e em trigonometria. Devido há natureza elastica do silicone, os efeitos resultantes da pressão do ar foram avaliados recurrendo às curvas de CP do XFOIL para calcular as cargas resultantes. Posteriormente uma análise MEF com o software comercial Ansys previu as deformações perpendiculares ao plano. Para dimensionar o sistema de actuação, um program foi escrito no Matlab. Optimização foi conseguida através da comparação do binário que o servo motor enacte na dobradiça com o somatório dos momentos resistentes (aerodinâmico, elastômero e junta flexível). Com toda a metodologia acima descrita, um desenho final, baseado no painel central da asa do modelo do ACC2019, foi apresentado. De forma a validar o conceito apresentado e os métodos utilizados, uma pequena secção (250 mm envergadura) foi fabricada com recurso a processos de manufactura de partes moldadas. Para o novo conceito, um processo de adesão para a folha de silicone foi pensado e este requeriu um molde próprio para o efeito. Depois de desmoldada, a secção foi trimada e o servo motor foi instalado para verificar a funcionalidade. Um último teste foi efectuado, realizando modificações à bancada de teste construída previamente, com a finalidade de comparar os momentos projectados com os do produto final

Evaluating the displacement field of paperboardpackages subjected to compression loading using digital image correlation (DIC)

CITATION: Fadiji, T.; Coetzee, C. J. & Opara, U. L. 2020. Evaluating the displacement field of paperboard packages subjected to compression loading using digital image correlation (DIC). Food and Bioproducts Processing, 123:60-71. doi:10.1016/j.fbp.2020.06.008The original publication is available at https://www.journals.elsevier.com/food-and-bioproducts-processingDigital image correlation (DIC) is a full-field non-contact optical technique for measuring displacements in experimental testing based on correlating several digital images taken during the test, particularly images before and after deformation. Application of DIC cuts across several fields, particularly in experimental solid mechanics; however, its potential application to paperboard packaging has not been fully explored. To preserve fresh horticultural produce during postharvest handling, it is crucial to understand how the packages deform under mechanical loading. In this study, 3D digital image correlation with two cameras and stereovision was used to determine the full-field displacement of corrugated paperboard packaging subjected to compression loading. Strain fields were derived from the displacement fields. Results obtained from the displacement fields showed the initiation and development of the buckling behaviour of the carton panels. The displacement was observed to be largely heterogeneous. The displacement field in the horizontal direction was smaller compared to that of vertical and out-of-plane directions. In addition, the strain variation increased as load increased, which could be a precursor to material failure. The technique proved to be efficient in providing relevant information on the displacement and strain fields at the surface panels of corrugated paperboard packages used for handling horticultural produce. In addition, it offers prospects for improved mechanical design of fresh produce packaging.https://www.sciencedirect.com/science/article/pii/S0960308520304430Publishers versio

Carbon flow analysis of the South African paper converting, paper recycling and end user stage of paper.

Masters Degree. University of KwaZulu-Natal, Durban.Abstract available in pdf

A Packing-Line Productivity Assessment of Particleboard Furniture

Malaysia, with its abundance of wood resources, is one of the traditional powerhouses of Asia's wood industry. In recent years, this sector has lost some of its edge simply because other countries have caught up, or have surpassed it in terms of competitiveness. Local manufacturers have no choice but to improve the production efficiency as well as the quality of their products if they want to remain competitive in the globalize market. In the production of panel particleboard furniture, the operations of packing department is more complicated and complex. The continuous packing process is affected by various factors, known and unknown, tangible and intangible. The objective of this paper is to study and analyze various factors contributing to the productivity of the packing line of particleboard furniture. The productivity and the frequency of the factors affecting the packing lines were measured and analyzed. The result showed that production planning, packing flow chart and work design (55%), insufficient of raw and supporting materials (21%), and the problems related to quality (14%) are the three most influencing factors to the productivity of packing lines, followed by insufficient of manpower arrangement (6%) and machinery breakdown (4%)