scholarly journals 3D Printed Hollow Off-Axis Profiles Based on Carbon Fiber-Reinforced Polymers: Mechanical Testing and Finite Element Method Analysis

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2949
Author(s):  
Martina Kalova ◽  
Sona Rusnakova ◽  
David Krzikalla ◽  
Jakub Mesicek ◽  
Radek Tomasek ◽  
...  

The aim of the paper is to design, manufacture, and test an off-axis composite profile of circular cross-section. Composite profile based on continuous carbon fibers reinforcing the onyx matrix, i.e., a matrix that consists of nylon and micro carbon fibers, was produced by fused deposition modeling (FDM) method. A buckling test of the six printed composite specimens was performed on a tensile test machine. The values of the experiment were compared with the values of the computational simulation using the Finite Element Method (FEM) analysis. The mean value of the experimentally determined critical force at which the composite profile failed was 3102 N, while the value of the critical force by FEM analysis was calculated to be 2879 N. Thus, reliability of the simulation to determine the critical force differed from the experimental procedure by only 7%. FEM analysis revealed that the primary failure of 3D printed composite parts was not due to loss of stability, but due to material failure. With great accuracy, the results of the comparison show that it is possible to predict the mechanical properties of 3D printed composite laminates on the basis of a theoretical model.

2020 ◽  
Vol 10 (6) ◽  
pp. 2139
Author(s):  
Betsy D. M. Chaparro-Rico ◽  
Daniele Cafolla ◽  
Marco Ceccarelli ◽  
Eduardo Castillo-Castaneda

Patients with neurological or orthopedic lesions require assistance during therapies with repetitive movements. NURSE (cassiNo-qUeretaro uppeR-limb aSsistive dEvice) is an arm movement aid device for both right- and left-upper limb. The device has a big workspace to conduct physical therapy or training on individuals including kids and elderly individuals, of any age and size. This paper describes the mechanism design of NURSE and presents a numerical procedure for testing the mechanism feasibility that includes a kinematic, dynamic, and FEM (Finite Element Method) analysis. The kinematic demonstrated that a big workspace is available in the device to reproduce therapeutic movements. The dynamic analysis shows that commercial motors for low power consumption can achieve the needed displacement, acceleration, speed, and torque. Finite Element Method showed that the mechanism can afford the upper limb weight with light-bars for a tiny design. This work has led to the construction of a NURSE prototype with a light structure of 2.6 kg fitting into a box of 35 × 45 × 30 cm. The latter facilitates portability as well as rehabilitation at home with a proper follow-up. The prototype presented a repeatability of ±1.3 cm that has been considered satisfactory for a device having components manufactured with 3D rapid prototyping technology.


Author(s):  
Tatsuo Nishizawa ◽  
Tadashi Fukuda ◽  
Saburo Matsuno ◽  
Kenji Himeno

In the design of concrete pavement, curling stresses caused by the temperature difference between the top and bottom surfaces of the slab should be calculated at the transverse joint edge in some cases. However, no such equation has been developed in the past. Accordingly, a curling stress equation was developed based on stress analysis using the finite-element method (FEM). In this FEM analysis, a concrete pavement and its transverse joint were expressed by means of a thin plate–Winkler foundation model and a spring joint model, respectively. Multiregression analysis was applied to the results of the FEM numerical calculation and, consequently, a curling stress equation was obtained. After comparing the calculated results of the equation with curling stress equations developed in the past, it was confirmed that the equation was valid and practical.


2020 ◽  
Vol 33 ◽  
pp. 101181 ◽  
Author(s):  
Anahita Ahmadi Soufivand ◽  
Nabiollah Abolfathi ◽  
Seyyed Ataollah Hashemi ◽  
Sang Jin Lee

2007 ◽  
Vol 336-338 ◽  
pp. 1531-1533
Author(s):  
Jian Qiang Qi ◽  
Yong Huang ◽  
Shi Xi Ouyang ◽  
Nan Li ◽  
Jiang Li ◽  
...  

By means of a finite element method model, the effects of property parameters of refractory on thermal stress of injection lance have been studied. The results show that the maximum thermal stress increases with the improvement of thermal conductivity and elastic modulus of refractory, while it decreases at first and then increases with the improvement of the coefficient of expansion of refractory.


2013 ◽  
Vol 586 ◽  
pp. 202-205 ◽  
Author(s):  
Milos Milosevic ◽  
Nenad Mitrovic ◽  
Vesna Miletić ◽  
Uroš Tatic ◽  
Andrea Ezdenci

Local polymerization stress occurs due to polymerization shrinkage of resin based composites adhesively bonded to tooth tissues. Shrinkage causes local displacements of cavity walls, with possible occurrence of micro-cracks in the enamel, dentin and/or material itself. In order to design a cavity for experimental testing of polymerization shrinkage of dental composites using 3D optical analysis, in this paper finite element method (FEM) was used to analyze numerical models with different cavity radiuses. 3D optical strain and displacement analysis of composite materials and cavity walls is limited by equipment sensitivity i.e. 0.01% for strain and 1 micron for displacement. This paper presents the development of 3D computer premolar models with varying cavity radiuses, and local stress, strain and displacement analysis using FEM. Model verification was performed by comparing obtained results with data from the scientific literature. Using the FEM analysis of local strains, displacements and stresses exerted on cavity walls, it was concluded that the model with 1 mm radius was optimal for experimental optical 3D displacement analysis.


2012 ◽  
Vol 170-173 ◽  
pp. 1837-1841
Author(s):  
Qiu Hua Duan ◽  
Lu Feng Yang ◽  
Meng Lin Lou

This paper mainly uses finite element method (FEM) to research how the bent-height influence on dynamic characteristic, acceleration reaction, dynamic water pressure, dynamic stress reaction of the aqueduct-water coupling structure seismic performance. Through calculation and analysis some significant results were obtained.


2018 ◽  
Vol 106 (1) ◽  
pp. 19-24
Author(s):  
Damian Biel ◽  
Tomasz Lipecki

Abstract Nowadays, the growing popularity of terrestrial laser scanners (TLS) allows to obtain a point cloud of many industrial objects along with classic surveying. However, the quality and model’s accuracy in comparison to a real shape seem to be a question, that must be further researched. It is crucial especially for Finite Element Method (FEM) analysis, which, being a part of technical design, estimate the values of construction’s dislocation and deformation. The article describes objects such as headgear with steel support and 4-post headframe with steel sheers. Both supports and sheers were modelled basing on point clouds. All the models were compared to the point cloud. The differences in models’ shape were calculated and the maximal values were determined. The results’ usefulness in FEM analysis was described.


1996 ◽  
Vol 100 (4) ◽  
pp. 2785-2786
Author(s):  
Hiroshi Wada ◽  
Takuji Koike ◽  
Toshimitsu Kobayashi ◽  
Kenji Ohyama ◽  
Tomonori Takasaka

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 797
Author(s):  
Marco Cicciù

Implantology, prosthodontics, and orthodontics in all their variants, are medical and rehabilitative medical fields that have greatly benefited from bioengineering devices of investigation to improve the predictability of clinical rehabilitations. The finite element method involves the simulation of mechanical forces from an environment with infinite elements, to a simulation with finite elements. This editorial aims to point out all the progress made in the field of bioengineering and medicine. Instrumental investigations, such as finite element method (FEM), are an excellent tool that allows the evaluation of anatomical structures and any facilities for rehabilitation before moving on to experimentation on animals, so as to have mechanical characteristics and satisfactory load cycle testing. FEM analysis contributes substantially to the development of new technologies and new materials in the biomedical field. Thanks to the 3D technology and to the reconstructions of both the anatomical structures and eventually the alloplastic structures used in the rehabilitations it is possible to consider all the mechanical characteristics, so that they could be analyzed in detail and improved where necessary.


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