Browsing NIAR: National Institute for Aviation Research by Title
Now showing items 18-37 of 57
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Damage initiation and fracture analysis of honeycomb core single cantilever beam sandwich specimens
(SAGE, 2020-04-27)Fracture testing and analysis of aerospace grade honeycomb core sandwich constructions using a single cantilever beam test methodology is presented here. Influence of various parameters such as facesheet thickness, core ... -
Damage mechanisms in tapered composite structures under static and fatigue loading
(DEStech Publications, 2019-09)In this work an integrated computational/experimental approach was developed to validate the predictive capabilities of State-of-the-Art (SoA) Progressive Damage Analysis (PDA) methods and tools. Specifically, a tapered ... -
Defects characterization and evaluation of their effects on compressive failure of composite components
(DEStech Publications, 2019-09)In the design and certification of composite structural components for aircrafts, compression and combined compression and shear loading cases have to be considered. Various forms of defects such as ply waviness, delamination ... -
Defects characterization, damage mapping, and property evaluation of composites
(DEStech Publications Inc., 2018)The presence of voids in the composite laminates can reduce the mechanical properties in composites and these voids can become precursors in the activation of other failure modes such as delamination. Knowing the volume ... -
Development and validation of finite element impact models of high-density UAS components for use in air-to-air collision simulations
(Taylor and Francis Inc., 2020-05-18)Understanding the severity of mid-air collisions between lightweight fixed-wing unmanned aerial systems (FW-UASs) and manned aircraft is a critical flight safety issue. Finite element models of high-density FW-UAS components ... -
Effects of refill friction stir spot weld spacing and edge margin on mechanical properties of multi-spot-welded panels
(MDPI AG, 2020-06-07)Refill friction stir spot welding (RFSSW) is an emerging technology for joining aerospace aluminum alloys. The aim of the study is to investigate the effects of the refill friction stir spot weld spacing and the edge margin ... -
Electroplating polymer based additive manufactured parts for enhanced structural performance
(DEStech Publications, 2021)Additive manufacturing has been adopted in many aerospace and defense applications to reduce weight and buy-to-fly ratios of low-volume high- complexity parts. Polymer-based additive manufacturing processes such as Fused ... -
An engineering approach to analyze damage initiation modes in tapered composite structures
(DEStech Publications Inc., 2018)In this work an engineering approach is demonstrated for analyzing damage initiation modes in tapered composite structures. The analysis methodology includes simulation of the non-linear static response of tapered composite ... -
Evaluation of ls-dyna mat162 for modeling composite fastener joints for high rates of loading
(American Institute of Aeronautics and Astronautics Inc., 2019-01)In the present work, the behavior of composite-fastener joints in bearing failure at dynamic stroke rates of 500 in/s, 300 in/s and 100 in/s has been evaluated through progressive damage analysis (PDA) material model in ... -
Experimental and numerical analysis of wrinkles influence on damage mechanisms and strength of L-shape cross-ply composite beams
(Elsevier, 2022-03-28)In this work, experimental and finite element (FE) analysis of L-shape cross-ply fiber-reinforced composite beams are carried out to investigate the effect of out-of-plane wrinkles on the interlaminar strength and competing ... -
Experimental Observations of Damage States in Unnotched and Notched 3D Orthogonal Woven Coupons Loaded in Tension
(American Institute of Aeronautics and Astronautics, 2021-12-29)This paper describes a series of unnotched and notched tensile tests on two 3D orthogonal woven architectures loaded in the warp direction. Dogbone specimens were used for the unnotched tests, and open-hole specimens were ... -
Fatigue damage modeling in laminated composite by using Rx-FEM and strength tracking method
(Elsevier Ltd, 2022-12-01)The durability and residual load carrying capacity of composite materials is of critical importance for increasing their applicability. Regularized eXtended Finite Element Method framework for discrete modeling of damage ... -
Fatigue damage modeling in laminated composites by using Rx-FEM and strength tracking method
(DEStech Publications, 2021-09)The durability and residual load carrying capacity of composite materials and structures is of critical importance for increasing their application across the industry. Regularized eXtended Finite Element Method (Rx-FEM) ... -
High rate testing of composite fastener joints with and without clamp-up
(DEStech Publications Inc., 2018)The NASA Advanced Composites Consortium (ACC) High Energy Dynamic Impact (HEDI) group has been investigating experimentally the effects of testing speed and fastener clamp-up on the behavior of single lap shear composite ... -
Induction heating of CF/PEKK laminates using homogenization techniques
(DEStech Publications, 2021)The primary heat generation mechanisms of carbon fiber reinforced thermoplastic laminates during induction heating are joule losses, junction heating with contact resistance and dielectric hysteresis. In relation, these ... -
Injection repair for restoration of composite properties
(SAMPE, 2019-03)Resin injection is a less intrusive method of repair and does not require near the post processing of other composite repair methods. However, until recently this method of repair has not allowed the restoration of the ... -
Integration of instance-based learning and computed torque control for an effective assist-as-needed support in human-exoskeleton interaction
(Association for Industry, Engineering and Management Systems (AIEMS), 2022-12)The physiological responses that arise from human-robot interaction may vary across subjects in magnitude and rate. Such individual variations may require instance-based learning over model-based learning algorithms. For ... -
Learning robotic grasping strategy based on natural-language object descriptions
(IEEE, 2018-10)Given the description of an object's physical attributes, humans can determine a proper strategy and grasp an object. This paper proposes an approach to determine grasping strategy for an anthropomorphic robotic hand simply ... -
Material state monitoring using embedded sensors for validating models for detecting process-induced damages in polymer composites
(DEStech Publications Inc., 2018)Composite material cure recipes are based on manufacturer-recommended cure cycle inputs, which are developed as a result of various stochastic cure kinetics models during the development of resin formulation. The time, ... -
Measuring and estimating rotary joint axes of an articulated robot
(IEEE, 2020-04-29)The aim of this article is to chronicle a novel methodology for measuring and estimating rotary joint axes of an articulated robot. The key contribution of the proposed methodology is a practical way of estimating rotary ...