scholarly journals Comparative Functional Morphology of Human and Chimpanzee Feet Based on Three-Dimensional Finite Element Analysis

2022 ◽  
Vol 9 ◽  
Author(s):  
Kohta Ito ◽  
Tomoya Nakamura ◽  
Ryo Suzuki ◽  
Takuo Negishi ◽  
Motoharu Oishi ◽  
...  
Keyword(s):  
Finite Element ◽  
Center Of Pressure ◽  
Three Dimensional ◽  
Axial Loading ◽  
The Body ◽  
Bipedal Locomotion ◽  
Human Foot ◽  
Foot Bones ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

To comparatively investigate the morphological adaptation of the human foot for achieving robust and efficient bipedal locomotion, we develop three-dimensional finite element models of the human and chimpanzee feet. Foot bones and the outer surface of the foot are extracted from computer tomography images and meshed with tetrahedral elements. The ligaments and plantar fascia are represented by tension-only spring elements. The contacts between the bones and between the foot and ground are solved using frictionless and Coulomb friction contact algorithms, respectively. Physiologically realistic loading conditions of the feet during quiet bipedal standing are simulated. Our results indicate that the center of pressure (COP) is located more anteriorly in the human foot than in the chimpanzee foot, indicating a larger stability margin in bipedal posture in humans. Furthermore, the vertical free moment generated by the coupling motion of the calcaneus and tibia during axial loading is larger in the human foot, which can facilitate the compensation of the net yaw moment of the body around the COP during bipedal locomotion. Furthermore, the human foot can store elastic energy more effectively during axial loading for the effective generation of propulsive force in the late stance phase. This computational framework for a comparative investigation of the causal relationship among the morphology, kinematics, and kinetics of the foot may provide a better understanding regarding the functional significance of the morphological features of the human foot.

A Three Dimensional Finite Element Analysis of Mechanical Stresses in the Human Knee Joint: Problem of Cartilage Destruction

2017 ◽  
Vol 32 ◽  
pp. 29-39 ◽  
Author(s):  
Zahra Trad ◽  
Abdelwahed Barkaoui ◽  
Moez Chafra
Keyword(s):  
Finite Element ◽  
Body Weight ◽  
Knee Joint ◽  
Knee Osteoarthritis ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
The Body ◽  
Medial Compartment ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Knee malalignment is considered one of the key biomechanical factors that influence the progression of knee osteoarthritis. In this context, a three-dimensional Finite Element model of the knee joint is developed and used to investigate the effect of the frontal plane femoro-tibial angle as well as the body weight load on the stress distribution in the knee cartilage and menisci. Therefore, the knee joint model is obtained through CAD software. Bones, articular cartilage and menisci are considered linear, elastic and isotropic materials. Ligaments were modelled using connectors. Consequently, contact pressures and equivalent stress (von-Mises) are calculated in Abaqus software. This model was validated using experimental and numerical results obtained by other authors. Results of this work demonstrated that; compressive stress and contact pressure on the medial compartment of the knee joint were found to be larger compared to those in the lateral compartment when the femoro-tibial angle and the body weight load increased from 0° to 12° varus and 500 N to 1250 N, respectively, suggesting that these two parameters might be risk factors for developing medial compartment knee osteoarthritis.

scholarly journals Comparative radiographic analysis of three-dimensional innate mobility of the foot bones under axial loading of humans and African great apes

2021 ◽  
Vol 8 (11) ◽  
Author(s):  
Takuo Negishi ◽  
Kohta Ito ◽  
Koh Hosoda ◽  
Takeo Nagura ◽  
Tomohiko Ota ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Three Dimensional ◽  
Axial Loading ◽  
Great Apes ◽  
Bipedal Locomotion ◽  
Human Foot ◽  
Foot Bones ◽  
Coupling Motion ◽  
African Great Apes ◽  
The Difference

The human foot is considered to be morphologically adapted for habitual bipedal locomotion. However, how the mobility and mechanical interaction of the human foot with the ground under a weight-bearing condition differ from those of African great apes is not well understood. We compared three-dimensional (3D) bone kinematics of cadaver feet under axial loading of humans and African great apes using a biplanar X-ray fluoroscopy system. The calcaneus was everted and the talus and tibia were internally rotated in the human foot, but such coupling motion was much smaller in the feet of African great apes, possibly due to the difference in morphology of the foot bones and articular surfaces. This study also found that the changes in the length of the longitudinal arch were larger in the human foot than in the feet of chimpanzees and gorillas, indicating that the human foot is more deformable, possibly to allow storage and release of the elastic energy during locomotion. The coupling motion of the calcaneus and the tibia, and the larger capacity to be flattened due to axial loading observed in the human foot are possibly morphological adaptations for habitual bipedal locomotion that has evolved in the human lineage.

scholarly journals Biomechanical assessment and finite element analysis of a simulated axial-loading experiment on a wrist protector model

2020 ◽  
Author(s):  
Jian Ying He ◽  
Li Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Axial Loading ◽  
Biomechanical Analysis ◽  
Control Group ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Experimental Group

Abstract Objective To evaluate the biomechanical analysis and effect of the wrist protector and provide a theoretical basis for wrist fractures and the optimal design of wrist protectors. Methods 6 cadaveric wrist models were axially loaded 600 N stress, and the stress magnitude and distribution of the experimental group (wearing wrist protectors) and control group were obtained. Furthermore, a three-dimensional finite element analysis was conducted to verify the scientificity and effectiveness of the models. Results The stresses on the radial distal palmar, ulnar distal palmar, radial distal dorsal, ulnar distal dorsal, radial proximal palmar and ulnar proximal palmar units in the experimental group were lower than those in the control group (P < 0.05). However, the stresses on the radial proximal dorsal and ulnar proximal dorsal units were higher than those in the control group (P>0.05). Conclusion The stress on the radioulnar palmar unit was high, while the radioulnar dorsal unit one was relatively low. Within the range of physiological loads, wearing wrist protectors can significantly reduce the stress on the radioulnar distal palmar, radioulnar proximal palmar and radioulnar distal dorsal units.

Three-dimensional finite element model to study temperature distribution in peripheral layers of human limbs immediately after physical exercise

2017 ◽  
Vol 10 (04) ◽  
pp. 1750053 ◽  
Author(s):  
Babita Kumari ◽  
Neeru Adlakha
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Physical Exercise ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
The Body ◽  
Dimensional Finite Element ◽  
Human Limb ◽  
Three Dimensional Finite Element

The physical exercise imposes challenges on the human thermoregulatory system, as heat exchange between the body and environment is substantially impaired, which can lead to decrease in performance and increased risk of heat illness. In view of above a three-dimensional finite element model is proposed to study the effect of different intensities of physical exercise on temperature distribution in peripheral regions of human limbs under moderate climatic conditions. Human limb is assumed to have a cylindrical cross-section. The peripheral region of the human limb is divided into three natural components, namely epidermis, dermis and subdermal tissues. The model incorporates the effect of important physiological parameters like blood mass flow rate, metabolic heat generation, and thermal conductivity of the tissues. Appropriate boundary conditions have been framed based on the physical conditions of the problem. The model is transformed into the discretized variational form and finite element method (FEM) has been employed to obtain the solution. The numerical results have been used to obtain the temperature profiles in the region immediately after exercise for an unsteady state case. The thermal information generated from the model can be useful for developing protocols for improving performance of sportsmen, military persons and labor-intensive workers.

scholarly journals Stress Analysis of Occlusal Forces in Canine Teeth and Their Role in the Development of Non-Carious Cervical Lesions: Abfraction

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Shihab A. Romeed ◽  
Raheel Malik ◽  
Stephen M. Dunne
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Axial Loading ◽  
Element Model ◽  
Lateral Loading ◽  
Cervical Lesions ◽  
Canine Tooth ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Non-carious cervical tooth lesions for many decades were attributed to the effects of abrasion and erosion mainly through toothbrush trauma, abrasive toothpaste, and erosive acids. However, though the above may be involved, more recently a biomechanical theory for the formation of these lesions has arisen, and the term abfraction was coined. The aim of this study was to investigate the biomechanics of abfraction lesions in upper canine teeth under axial and lateral loading conditions using a three-dimensional finite element analysis. An extracted human upper canine tooth was scanned byμCT machine (Skyscan, Belgium). TheseμCT scans were segmented, reconstructed, and meshed using ScanIP (Simpleware, Exeter, UK) to create a three-dimensional finite element model. A 100 N load was applied axially at the incisal edge and laterally at 45° midpalatally to the long axis of the canine tooth. Separately, 200 N axial and non-axial loads were applied simultaneously to the tooth. It was found that stresses were concentrated at the CEJ in all scenarios. Lateral loading produced maximum stresses greater than axial loading, and pulp tissues, however, experienced minimum levels of stresses. This study has contributed towards the understanding of the aetiology of non-carious cervical lesions which is a key in their clinical management.

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