Analytical Characterization and Experimental Validation of the Material Extrusion Wave Infill for Thin-Walled Structures

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Robert S. Chisena ◽  
Albert J. Shih
Keyword(s):  
Load Capacity ◽  
Analytical Models ◽  
Material Extrusion ◽  
Polyamide 12 ◽  
Thin Walled Structures ◽  
Nylon 12 ◽  
Thin Walled ◽  
Flexural Tests ◽  
Relative Root ◽  
Fabrication Time

Abstract The wave infill for material extrusion (MEX) of the thin-walled structure (TWS) is presented. The wave infill, a lightweight truss-like porous core structure sandwiched between two outer walls, is an efficient toolpath pattern for the MEX of TWS. Analytical models for predicting the stiffness, load capacity, fabrication time, and mass were established for two orthogonal in-plane and layer-to-layer variations inherent in MEX wave infill parts. Rectangular prism, four-point flexural bending specimens representing the in-plane and layer-to-layer orientations with wave infill were fabricated by MEX of polyamide-12 (Nylon-12) material. From these specimens, fabrication time and mass were measured, and four-point flexural tests were conducted to measure the stiffness and load capacity of the beam. Analytical models were compared with the experimental measurements to identify their predictive capabilities. Stiffness for in-plane and layer-to-layer orientations was predicted well with the relative root-mean-square error (RRMSE) of 7% and 6%, respectively. Load capacity in in-plane and layer-to-layer orientations had the RRMSE of 23% and 22%, respectively. Fabrication time and mass were predicted well with a RRMSE of 7% and 6%, respectively. The methods established in this study are the foundation for optimal design and MEX of wave infill TWSs with generalized loads.

Application of Finite Strip Method in Vehicle Design: Part 2 of 2—Post Buckling Analysis of Thin Walled Structures

2011 ◽  
Author(s):  
Umesh Gandhi ◽  
Stephane Roussel ◽  
K. Furusu ◽  
T. Nakagawa
Keyword(s):  
Load Capacity ◽  
High Strength ◽  
Maximum Load ◽  
Element Formulation ◽  
Tangent Stiffness Matrix ◽  
Finite Strip ◽  
Thin Walled Structures ◽  
Non Linear ◽  
Post Buckling ◽  
Thin Walled

Thin walled parts of high strength steel, under compressive loads are likely to buckle locally, and then depending on geometry and material properties the section may continue to carry additional load. For the post buckling conditions the deformations are large but finite. Therefore we need to consider geometrical non linearity in the calculations. In this paper we are extending the linear finite strip element formulation to include geometrical non linearity. Method to derive secant and tangent stiffness matrix for non linear finite strip element is developed and then the element formulation is verified for inplane and center load on a plate using Newton Raphson solver. The new non linear finite strip element can be useful in estimating maximum load capacity (including post buckling) of thin walled structures from 2D data.

scholarly journals The Numerical Investigation of Thin-Walled Beams with Modified C-Sections

2018 ◽  
Vol 38 (1) ◽  
pp. 57-66
Author(s):  
Michał Grenda
Keyword(s):  
Numerical Investigation ◽  
Cross Sections ◽  
Local Buckling ◽  
Limit Load ◽  
Analytical Models ◽  
Thin Walled Structures ◽  
Finite Strip Method ◽  
Walled Channel ◽  
Thin Walled ◽  
The Stability

Abstract Demand for thin-walled structures has been increasing for many years. Cold- formed, thin-walled channel beams are the subject of presented research. The local elastic buckling and limit load of these beams subjected to pure bending are investigated. This study includes numerical investigation called the Finite Strip Method (FSM). The presented results give a deep insight into behaviour of such beams and may be used to validate analytical models. The number of works devoted to the theory of thin-walled structures has been steadily growing in recent years. It means that is an increasing interest in practical methods of manufacturing cold-formed thin-walled beams with complicated cross-sections, including also beams with web stiffeners. The ratio of transverse dimensions of beam to its wall-thickness is high, therefore, thin-walled beams are prone to local buckling that may interact with other buckling modes. The stability constraints should be always considered when using cold-formed thin-walled beams.

scholarly journals Physical Tests of Alternative Connections of Different High Roof Purlins Regarding Upward Loading

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 512
Author(s):  
Miroslav Rosmanit ◽  
Přemysl Pařenica ◽  
Oldřich Sucharda ◽  
Petr Lehner
Keyword(s):  
Bearing Capacity ◽  
Load Capacity ◽  
Load Bearing Capacity ◽  
Physical Test ◽  
Load Bearing ◽  
Thin Walled Structures ◽  
Load Carrying ◽  
Physical Tests ◽  
Thin Walled ◽  
The Individual

Thin-walled cold-rolled sections are used in the construction industry, especially in the roofing of large-span halls. The load-bearing capacity of a thin-walled structure depends to a large extent on the load-bearing capacity of the details at the point of attachment to the structure and the interconnection of the individual thin-walled elements. Therefore, in the case of thin-walled structures, it is necessary to use additional structural elements such as local reinforcement, stabilising elements, supports, and other structural measures such as the doubling of profiles. This paper focused on the behaviour of tall Z300 and Z350 mm thin-walled trusses at the connection to the superstructure regarding upward loading (e.g., wind suction and so on). Two section thicknesses, 1.89 mm and 2.85 mm, were experimentally analysed. Furthermore, two types of connections were prepared, more precisely without and with a reinforced buckle. The experiments aimed to investigate the behaviour and load-carrying capacity of the detail of the roof truss connections to the supporting structure. The resulting load capacity values were compared with normative approaches. Analyses of the details of the bolt in the connection are also presented. The paper presents a practical evaluation of the physical test on real structural members.

Frame-Monolithic Technology of Construction of Low-Rise Buildings Made of Foam Gypsum and Steel Thin-Walled Structures

2018 ◽  
Vol 762 (8) ◽  
pp. 36-39 ◽  
Author(s):  
B.G. BULATOV ◽  
◽  
R.I. SHIGAPOV ◽  
M.A. IVLEV ◽  
I.V. NEDOSEKO ◽  
...  
Keyword(s):  
Thin Walled Structures ◽  
Thin Walled

scholarly journals Fracture Mechanical Analysis of Thin-Walled Cylindrical Shells with Cracks

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 592
Author(s):  
Feng Yue ◽  
Ziyan Wu
Keyword(s):  
Fracture Mechanics ◽  
Tensile Stress ◽  
Failure Modes ◽  
Cylindrical Shells ◽  
Crack Tip ◽  
Mechanical Analysis ◽  
J Integral ◽  
Thin Walled Structures ◽  
Circumferential Tensile Stress ◽  
Thin Walled

The fracture mechanical behaviour of thin-walled structures with cracks is highly significant for structural strength design, safety and reliability analysis, and defect evaluation. In this study, the effects of various factors on the fracture parameters, crack initiation angles and plastic zones of thin-walled cylindrical shells with cracks are investigated. First, based on the J-integral and displacement extrapolation methods, the stress intensity factors of thin-walled cylindrical shells with circumferential cracks and compound cracks are studied using linear elastic fracture mechanics, respectively. Second, based on the theory of maximum circumferential tensile stress of compound cracks, the number of singular elements at a crack tip is varied to determine the node of the element corresponding to the maximum circumferential tensile stress, and the initiation angle for a compound crack is predicted. Third, based on the J-integral theory, the size of the plastic zone and J-integral of a thin-walled cylindrical shell with a circumferential crack are analysed, using elastic-plastic fracture mechanics. The results show that the stress in front of a crack tip does not increase after reaching the yield strength and enters the stage of plastic development, and the predicted initiation angle of an oblique crack mainly depends on its original inclination angle. The conclusions have theoretical and engineering significance for the selection of the fracture criteria and determination of the failure modes of thin-walled structures with cracks.

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