Verification and further study on method of measuring contact force between mortise and tenon joint

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 263-276
Author(s):  
Wei-Lian Fu ◽  
Hui-Yuan Guan ◽  
Xin-Yi Zhang

This work verified the direct measuring method of the contact force and its relaxation behavior between mortise and tenon joints through withdrawal load resistance testing of T-shaped mortise-and-tenon joint specimens. Further, it also studied the influence of wood species, beech (Fagus orientalis Lipsky) and Mongolian Scots pine (Pinus sylvestris var. mongolica), interference fitness (0.1, 0.2, 0.3, and 0.4 mm; 0.2, 0.4, 0.6, and 0.8 mm), and wood grain orientation (radial, diagonal, and tangential) on the contact force and its relaxation. The results showed that the direct measuring method had good feasibility for measuring the contact force and its relaxation of the beech and it showed good feasibility on measuring initial contact force of pine. However, it showed low feasibility for measuring the relaxed contact force when the interference was 0.2 mm, but showed good feasibility on measuring the relaxed contact force with larger interference of pine. Interference fitness, wood grain orientation, and wood species had a significant effect on initial contact force and contact force after 5 h relaxation. This study showed feasibility and application scope of the method for direct measuring contact force and provided additional fundamental data to contribute to further study of the internal mechanical mechanism of mortise and tenon joints.

BioResources ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. 5608-5616
Author(s):  
Wen Gang Hu ◽  
Hui Wan ◽  
Hui Yuan Guan

A new method of testing mechanical properties of mortise-and-tenon joints is put forward. The contact force relaxation behavior of joints for 3 h with tenons in different grain orientations and tenon fits were studied. The results showed that the initial and final contact force of joints with tenons in radial grain orientation were all larger than those in tangential grain orientation in the same tenon fit. The regression equations generated in this paper were able to predict the contact force relaxation behavior of joints with tenons in different grain orientations, tenon fits, and time, and the errors were all within 20%. In addition, the ratio of loss for contact force of joints with tenons in radial grain orientations was greater than that with tenons in tangent in the same tenon fit. The ratios of loss decreased from 51% to 31% in two grain orientations of tenon with tenon fits increasing from 0.2 mm to 0.5 mm with an increment of 0.1 mm. The method proposed in this paper was able to predict the contact force relaxation of mortise-and-tenon joints. The relaxation of contact force in a joint should be considered when designing mortise-and-tenon joint furniture.


1999 ◽  
Vol 11 (4) ◽  
pp. 274-282 ◽  
Author(s):  
Takayoshi Yamada ◽  
◽  
Sushanta Kumar Saha ◽  
Nobuharu Mimura ◽  
Yasuyuki Funahashi ◽  
...  

We analyze stability of planar grasp using a 2D virtual spring model. A 2D virtual spring model is widely used to explore frictionless grasp, but the direction of contact force has not been studied for a grasped object displaced by external disturbance. Finger displacement is restricted to the normal at initial contact. We introduce a 2D spring model for a frictionless case. The direction of contact force is explicitly formulated. Using potential energy, we analyze stability of frictionless grasp and show that the 1D-spring model is a special case of our proposed 2D-spring model. Frictional grasp stability is also studied using rolling contact. Numerical examples of 2-fingered grasp demonstrate the effects of parameters such as spring stiffness and contact force. It is shown that an optimum force exists for stabilizing frictionless grasp. It is proved that friction enhances grasp stability from the relationship between frictionless and frictional stiffness matrices. Stiffness conditions for stabilizing 3-fingered grasp is clarified.


2001 ◽  
Vol IV.01.1 (0) ◽  
pp. 167-168
Author(s):  
Sei NAGASAKA ◽  
Mitsuru IKEDA ◽  
Hiroki SATO

Holzforschung ◽  
2005 ◽  
Vol 59 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Milena Properzi ◽  
Jean-Michel Leban ◽  
Antonio Pizzi ◽  
Stephanie Wieland ◽  
Frederic Pichelin ◽  
...  

Abstract Wood grain orientation differences in the two surfaces to be bonded yield bondlines of different strength in no-adhesives wood welding. Longitudinal wood grain bonding of tangential and radial wood sections yields an approximately 10% difference in strength results of the joint. Cross-grain (±90°) bonding yields instead a much lower strength result, roughly half that observed for pieces bonded with the grain parallel to each other. These differences can be explained by the very marked effect that homogeneity of fibre orientation is known to have on fibre–matrix composites. Oak yields lower results than beech and maple and is more sensitive to welding conditions. Differences in both anatomical and wood constituent composition can account for this difference in performance. Contrary to the other wood species, oak always presents joint bondlines where little or no increase in density at the interface is noticed. This explains its somewhat lower strength results. This is based on the different mode of bonding predominant in this species, while the other species present two different modes of bonding. Thus, two types of bondlines are observed by scanning electron microscopy (SEM): (i) bondlines where entangled fibre–matrix composites are formed at the interface and (ii) bondlines in which direct welding of the cell walls occurs, just by fused intercellular material or cell surface material. In this latter case the cells remain flat, without an entangled fibre–matrix composite being formed. This is the almost exclusively predominant case for oak. Both cases and even hybrid cases between the two have also been observed in beech.


2006 ◽  
Vol 96 (1) ◽  
pp. 27-39 ◽  
Author(s):  
L. J. Berryman ◽  
J. M. Yau ◽  
S. S. Hsiao

In this study we investigate the haptic perception of object size. We report the results from four psychophysical experiments. In the first, we ask subjects to discriminate the size of objects that vary in surface curvature and compliance while changing contact force. We show that objects exhibit size constancy such that perception of object size using haptics does not change with changes in contact force. Based on these results, we hypothesize that size perception depends on the degree of spread between the digits at initial contact with objects. In the second experiment, we test this hypothesis by having subjects continuously contact an object that changes dynamically in size. We show that size perception takes into account the compliance of the object. In the third and fourth experiments we attempt to separate the individual contributions of proprioceptive and cutaneous input. In the third, we test the ability of subjects to perceive object size after altering the sensitivity of cutaneous receptors with adapting vibratory stimuli. The results from this experiment suggest that initial contact is signaled by the cutaneous slowly adapting type 1 afferents (SA1) and/or the rapidly adapting afferents (RA). In the last experiment, we block cutaneous input at the site of contact by anesthetizing the digital nerves and show that proprioceptive information alone provides only a rough estimate of object size. We conclude that the perception of object size depends on inputs from SA1 and possibly RA afferents, combined with inputs from proprioceptive afferents that signal the spread between digits.


Nativa ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 508-517
Author(s):  
Germano Slominski Burakouski ◽  
Everton Hillig ◽  
Fabiane Salles Ferro ◽  
Gabriel De Magalhães Miranda

A exploração madeireira e as conversões de áreas de florestas para uso alternativo do solo na região Amazônica, em especial no estado do Amapá, resultam em grandes quantidades de madeira residual que em geral são abandonadas em campo. Essa problemática da geração de resíduos florestais e principalmente do desperdício e da falta de alternativas para o seu uso apropriado, resultou nesta proposta de pesquisa que teve como objetivo a produção de móveis rústicos artesanais como uma alternativa para o uso da madeira residual da floresta Amazônica. Foram coletados resíduos de madeira deixados no campo após a colheita de floresta Amazônica manejada, destinando-os à fabricação de mobiliário rústico, obtendo como resultado final os seguintes protótipos: banco peça de tora única, balcão para barzinho, aparador de madeira, pia de madeira, mesinha de centro com tampo de madeira, mesinha de centro com tampo de vidro. Foi testada a viabilidade técnica para fabricação artesanal das peças de mobiliário utilizando máquinas e ferramentas portáteis. Os resíduos de madeira se mostraram excelente fonte de matéria-prima para movelaria rústica possibilitando múltiplas alternativas de designs, apesar de certas dificuldades terem sido evidenciadas no decorrer do processo como: peso, dureza, orientação da grã da madeira, entre outras que, no entanto, não impossibilitaram a produção dos móveis. O uso da madeira residual para fabricação de móveis rústicos pode se constituir num novo e empreendedor negócio para a região Amazônica, contribuindo para a geração de renda local. Verificou-se que o método empregado proporcionou a produção de móveis originais, o que agrega valor à sua comercialização. Palavras-chave: trabalho artesanal; empreendedorismo; projeto.   Rustic furniture production with wood residues from the Amazon forest   ABSTRACT: Harvesting and conversions of forest areas to alternative land use in the Amazon region, especially in the Amapá state, result in large amounts of wood residues that are generally abandoned. This problem about the forest residues and mainly of its loss and the lack of alternatives for its proper use, resulted in this research proposal that aimed to produce handcrafted rustic furniture as an alternative to the use of wood residues from the Amazon forest. Wood residues left in the field after harvesting the managed Amazon forest were collected and destined for the manufacture of rustic furniture, obtaining the following prototypes as a final result:  log bench, bar counter, wood dresser, wood sink, coffee table with wood top, coffee table with glass top. The technical feasibility of handcrafting furniture pieces using portable machines and tools were tested. Wood residues proved to be an excellent source of raw material for rustic furniture, enabling multiple design alternatives, although certain difficulties were evidenced during the process such as: weight, hardness, wood grain orientation, among others that did not prevent the furniture production. The use of wood residues to rustic furniture manufacture can constitute a new and entrepreneurial business for the Amazon region, contributing to the generation of local income. It was found that the method used provided the production of original furniture, which adds value to its marketing. Keywords: artisan work; entrepreneurship; design.


2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Guanci Chen ◽  
Ge Wen ◽  
Zhengming Xiao ◽  
Hongjun San

Measuring and verification of contact force in a rolling element bearing is a big problem. In this study, a new measuring method for contact force in a large-scale ball bearing is developed. The idea is to measure the deformation under the ball–race contact by displacement sensor at first, and the displacement of the end face of load bearing ring is also measured to determine the contact angle of ball–race contact. Then, the corresponding theory is developed to calculate the contact angle of ball–race contact by the displacement of the end face of load bearing ring. At last, the ball–race contact force is determined by accurately calculating through finite element method (FEM). Results show that the relation between contact force and deformation of measuring surface which is under ball–race contact is linear. The position of ball greatly affects the contact angle of ball–race contact. The contact angle of the ball which is near the arm of force is larger than that of the ball which is far from the arm of force. On the contrary, the measuring deformation of ball–race contact that is near the arm of force is less than that of ball–race contact that is far from the arm of force. The method developed here is only suitable for large-scale rolling element bearing because of the size constraint of the sensor.


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