scholarly journals Fault-tolerant elastic–plastic lattice material

2019 ◽  
Vol 378 (2162) ◽  
pp. 20190107 ◽  
Author(s):  
Michael Ryvkin ◽  
Viacheslav Slesarenko ◽  
Andrej Cherkaev ◽  
Stephan Rudykh
Keyword(s):  
Energy Absorption ◽  
Fault Tolerant ◽  
Three Dimensional ◽  
Uniaxial Tensile ◽  
Elastoplastic Material ◽  
Beam Elements ◽  
Initial Stage ◽  
Final Failure ◽  
Thin Beams ◽  
Beam Lattice

The paper describes a fault-tolerant design of a special two-dimensional beam lattice. The morphology of such lattices was suggested in the theoretical papers (Cherkaev and Ryvkin 2019 Arch. Appl. Mech. 89 , 485–501; Cherkaev and Ryvkin 2019 Arch. Appl. Mech. 89 , 503–519), where its superior properties were found numerically. The proposed design consists of beam elements with two different thicknesses; the lattice is macro-isotropic and stretch dominated. Here, we experimentally verify the fault-tolerant properties of these lattices. The specimens were three-dimensional-printed from the VeroWhite elastoplastic material. The lattice is subjected to uniaxial tensile loading. Due to its morphology, the failed beams are evenly distributed in the lattice at the initial stage of damage; at this stage, the material remains intact, preserves its bearing ability, and supports relatively high strains before the final failure. At the initial phase of damage, the thinner beams buckle; then another group of separated thin beams plastically yield and rupture. The fatal macro-crack propagates after the distributed damage reaches a critical level. This initial distributed damage stage allows for a better energy absorption rate before the catastrophic failure of the structure. The experimental results are supported by simulations which confirm that the proposed fault-tolerant material possesses excellent energy absorption properties thanks to the distributed damage stage phenomenon. This article is part of the theme issue ‘Modelling of dynamic phenomena and localization in structured media (part 2)’.

scholarly journals Crash Characteristics of Partially Quenched Curved Products by Three-Dimensional Hot Bending and Direct Quench

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1322
Author(s):  
Atsushi Tomizawa ◽  
Sanny Soedjatmiko Hartanto ◽  
Kazuo Uematsu ◽  
Naoaki Shimada
Keyword(s):  
Energy Absorption ◽  
Three Dimensional ◽  
Crash Test ◽  
Initial Stage ◽  
Automotive Parts ◽  
Fundamental Research ◽  
Vehicle Technologies ◽  
Crash Characteristics ◽  
Crash Tests ◽  
Direct Quench

Recently, improvement of hybrid and electric vehicle technologies, equipped with batteries, continues to solve energy and environmental problems. Lighter weight and crash safety are required in these vehicles body. In order to meet these requirements, three-dimensional hot bending and direct quench (3DQ) technology, which enables to form hollow tubular automotive parts with a tensile strength of 1470 MPa or over, has been developed. In addition, this technology enables to produce partially quenched automotive parts. In this study, the crash characteristics of 3DQ partially quenched products were investigated as the fundamental research of the design for improving the energy absorption. Main results are as follows: (1) for partially quenched straight products in axial crash test, buckling that occurs at nonquenched portion can be controlled; (2) for the nonquenched conventional and overall-quenched curved products, buckling occurs at the bent portion at the initial stage in axial crash tests, and its energy absorption is low; (3) by optimizing partially quench conditions, buckling occurrence can be controlled; and (4) In this study, the largest energy absorption was obtained from the partially quenched curved product, which was 84.6% larger than the energy absorption of the conventional nonquenched bent product in crash test.

scholarly journals Experimental Research of Selected Lattice Structures Developed with 3D Printing Technology

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 378
Author(s):  
Paweł Bogusz ◽  
Arkadiusz Popławski ◽  
Michał Stankiewicz ◽  
Bartłomiej Kowalski
Keyword(s):  
Energy Absorption ◽  
Experimental Research ◽  
Lattice Structures ◽  
Absorbed Energy ◽  
Photographic Material ◽  
Beam Elements ◽  
Initial Stage ◽  
Minimum Cross Section ◽  
Different Characteristics ◽  
Additive Technique

This paper presents the results of the experimental research of 3D structures developed with an SLA additive technique using Durable Resin V2. The aim of this paper is to evaluate and compare the compression curves, deformation process and energy-absorption parameters of the topologies with different characteristics. The structures were subjected to a quasi-static axial compression test. Five different topologies of lattice structures were studied and compared. In the initial stage of the research, the geometric accuracy of the printed structures was analysed through measurement of the diameter of the beam elements at several selected locations. Compression curves and the stress history at the minimum cross-section of each topology were determined. Energy absorption parameters, including absorbed energy (AE) and specific absorbed energy (SAE), were calculated from the compression curves. Based on the analysis of the photographic material, the failure mode was analysed, and the efficiency of the topologies was compared.

scholarly journals Compressive behaviours of octet-truss lattices

2020 ◽  
Vol 234 (16) ◽  
pp. 3257-3269 ◽  
Author(s):  
Yifan Li ◽  
Huaiyuan Gu ◽  
Martyn Pavier ◽  
Harry Coules
Keyword(s):  
Failure Modes ◽  
Density Ratio ◽  
Three Dimensional ◽  
Compressive Load ◽  
High Strength ◽  
Detailed Comparison ◽  
Compressive Response ◽  
Beam Elements ◽  
Structural Applications ◽  
Octet Truss

Octet-truss lattice structures can be used for lightweight structural applications due to their high strength-to-density ratio. In this research, octet-truss lattice specimens were fabricated by stereolithography additive manufacturing with a photopolymer resin. The mechanical properties of this structure have been examined in three orthogonal orientations under the compressive load. Detailed comparison and description were carried out on deformation mechanisms and failure modes in different lattice orientations. Finite element models using both beam elements and three-dimensional solid elements were used to simulate the compressive response of this structure. Both the load reaction and collapse modes obtained in simulations were compared with test results. Our results indicate that three-dimensional continuum element models are required to accurately capture the behaviour of real trusses, taking into account the effects of finite-sized beams and joints.

Numerical and experimental investigation for enhancing the energy absorption capacity of the novel three-dimensional printed sandwich structures

2021 ◽  
pp. 146442072199749
Author(s):  
H Geramizadeh ◽  
S Dariushi ◽  
S Jedari Salami
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
The Novel ◽  
Energy Absorption Capacity ◽  
Fused Deposition ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Vertical Walls

The current study focuses on designing the optimal three-dimensional printed sandwich structures. The main goal is to improve the energy absorption capacity of the out-of-plane honeycomb sandwich beam. The novel Beta VI and Alpha VI were designed in order to achieve this aim. In the Beta VI, the connecting curves (splines) were used instead of the four diagonal walls, while the two vertical walls remained unchanged. The Alpha VI is a step forward on the Beta VI, which was promoted by filleting all angles among the vertical walls, created arcs, and face sheets. The two offered sandwich structures have not hitherto been provided in the literature. All models were designed and simulated by the CATIA and ABAQUS, respectively. The three-dimensional printer fabricated the samples by fused deposition modeling technique. The material properties were determined under tensile, compression, and three-point bending tests. The results are carried out by two methods based on experimental tests and finite element analyses that confirmed each other. The achievements provide novel insights into the determination of the adequate number of unit cells and demonstrate the energy absorption capacity of the Beta VI and Alpha VI are 23.7% and 53.9%, respectively, higher than the out-of-plane honeycomb sandwich structures.

scholarly journals Numerical Analysis of the Perforated Steel Sheets Under Uni-Axial Tensile Force

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 632 ◽  
Author(s):  
Ahmed M. Sayed
Keyword(s):  
Load Capacity ◽  
Tensile Force ◽  
Three Dimensional ◽  
Tensile Load ◽  
Experimental Tests ◽  
Strain Engineering ◽  
Uniaxial Tensile ◽  
Fe Model ◽  
Stress Strain ◽  
Steel Sheets

The perforated steel sheets have many uses, so they should be studied under the influence of the uniaxial tensile load. The presence of these holes in the steel sheets certainly affects the mechanical properties. This paper aims at studying the behavior of the stress-strain engineering relationships of the perforated steel sheets. To achieve this, the three-dimensional finite element (FE) model is mainly designed to investigate the effect of this condition. Experimental tests were carried out on solid specimens to be used in the test of model accuracy of the FE simulation. Simulation testing shows that the FE modeling revealed the ability to calculate the stress-strain engineering relationships of perforated steel sheets. It can be concluded that the effect of a perforated rhombus shape is greater than the others, and perforated square shape has no effect on the stress-strain engineering relationships. The efficiency of the perforated staggered or linearly distribution shapes with the actual net area on the applied loads has the opposite effect, as it reduces the load capacity for all types of perforated shapes. Despite the decrease in load capacity, it improves the properties of the steel sheets.

scholarly journals Effect of Uniaxial Tensile Cyclic Loading Regimes on Matrix Organization and Tenogenic Differentiation of Adipose-Derived Stem Cells Encapsulated within 3D Collagen Scaffolds

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Gayathri Subramanian ◽  
Alexander Stasuk ◽  
Mostafa Elsaadany ◽  
Eda Yildirim-Ayan
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Expression Profiles ◽  
Three Dimensional ◽  
Uniaxial Tensile ◽  
Adipose Derived Stem Cells ◽  
Collagen Scaffolds ◽  
Differentiation Potential ◽  
Tenogenic Differentiation ◽  
Matrix Organization

Adipose-derived mesenchymal stem cells have become a popular cell choice for tendon repair strategies due to their relative abundance, ease of isolation, and ability to differentiate into tenocytes. In this study, we investigated the solo effect of different uniaxial tensile strains and loading frequencies on the matrix directionality and tenogenic differentiation of adipose-derived stem cells encapsulated within three-dimensional collagen scaffolds. Samples loaded at 0%, 2%, 4%, and 6% strains and 0.1 Hz and 1 Hz frequencies for 2 hours/day over a 7-day period using a custom-built uniaxial tensile strain bioreactor were characterized in terms of matrix organization, cell viability, and musculoskeletal gene expression profiles. The results displayed that the collagen fibers of the loaded samples exhibited increased matrix directionality with an increase in strain values. Gene expression analyses demonstrated that ASC-encapsulated collagen scaffolds loaded at 2% strain and 0.1 Hz frequency showed significant increases in extracellular matrix genes and tenogenic differentiation markers. Importantly, no cross-differentiation potential to osteogenic, chondrogenic, and myogenic lineages was observed at 2% strain and 0.1 Hz frequency loading condition. Thus, 2% strain and 0.1 Hz frequency were identified as the appropriate mechanical loading regime to induce tenogenic differentiation of adipose-derived stem cells cultured in a three-dimensional environment.

An Equivalent 3-D Method for Analyzing Orthogonally Stiffened Plate Structures

1987 ◽  
Vol 31 (02) ◽  
pp. 101-106
Author(s):  
Kyu Nam Cho ◽  
William S. Vorus
Keyword(s):  
Bridge Decks ◽  
Three Dimensional ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Work Related ◽  
Beam Elements ◽  
Proposed Model ◽  
The Relationship

A new three-dimensional method is proposed for analyzing orthogonally stiffened grillage structures. The method is based on earlier work related to bridge decks. The relationship between system displacement and loads is described mathematically, and matrices are developed to examine the shear compatibility between plate and beam elements. The paper concludes with a comparison between deflections obtained by several different procedures and the proposed model.

scholarly journals Numerical Simulation of Temperature Distribution in the Glass Fiber Epoxy Composites during Microwave Curing

2018 ◽  
Vol 206 ◽  
pp. 03001
Author(s):  
X Zhang ◽  
X L Chang ◽  
R L Ma ◽  
L Zhang ◽  
X D Chen ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Glass Fiber ◽  
Three Dimensional ◽  
Coupled Model ◽  
Curing Process ◽  
Epoxy Ring ◽  
Microwave Curing ◽  
Composite Ring ◽  
Initial Stage ◽  
Field Temperature

A three-dimensional coupled model of electromagnetic field, temperature field and curing degree field was established. Based on this model, the simulation of microwave curing process of glass fiber epoxy ring was realized, and the temperature distribution at different time was obtained. Numerical results indicate that the temperature difference within the composite ring is mainly formed in the initial stage during microwave curing.

Improvement and validation of a physically based model for the shear and transverse crushing of orthotropic composites

2018 ◽  
Vol 53 (12) ◽  
pp. 1681-1696 ◽  
Author(s):  
Sérgio Costa ◽  
Thomas Bru ◽  
Robin Olsson ◽  
André Portugal
Keyword(s):  
Current Model ◽  
Three Dimensional ◽  
Fracture Plane ◽  
Damage Growth ◽  
Pressure Dependency ◽  
Orthotropic Composites ◽  
Fabric Composites ◽  
Final Failure ◽  
Physically Based ◽  
Nonlinear Shear

This paper details a complete crush model for composite materials with focus on shear dominated crushing under a three-dimensional stress state. The damage evolution laws and final failure strain conditions are based on data extracted from shear experiments. The main advantages of the current model include the following: no need to measure the fracture toughness in shear and transverse compression, mesh objectivity without the need for a regular mesh and finite element characteristic length, a pressure dependency of the nonlinear shear response, accounting for load reversal and some orthotropic effects (making the model suitable for noncrimp fabric composites). The model is validated against a range of relevant experiments, namely a through-the-thickness compression specimen and a flat crush coupon with the fibres oriented at 45° and 90° to the load. Damage growth mechanisms, orientation of the fracture plane, nonlinear evolution of Poisson's ratio and energy absorption are accurately predicted.

Engineering Analysis of Shoulder Dystocia in the Human Birth Process by the Finite Element Method

1992 ◽  
Vol 206 (4) ◽  
pp. 243-250 ◽  
Author(s):  
A Meghdari ◽  
R Davoodi ◽  
F Mesbah
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Shoulder Dystocia ◽  
Point Of View ◽  
Engineering Analysis ◽  
The Finite Element Method ◽  
Birth Process ◽  
Beam Elements ◽  
Finite Element Package ◽  
Human Birth

This paper presents an engineering analysis of shoulder dystocia (SD) in the human birth process which usually results in damaging the brachial plexus nerves and the humerus and/or clavicle bones of the baby. The goal is to study these injuries from the mechanical engineering point of view. Two separate finite element models of the neonatal neck and the clavicle bone have been simulated using eight-node three-dimensional elements and beam elements respectively. Simulated models have been analysed under suitable boundary conditions using the ‘SAP80’ finite element package. Finally, results obtained have been verified by comparing them with published clinical and experimental observations.

Sign in / Sign up

Export Citation Format

Share Document