Browsing NIAR: National Institute for Aviation Research by Title
Now showing items 23-42 of 53
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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 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 ... -
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 ... -
Mechanics-based model for rapid prediction of low-velocity impact damage in composite laminates
(American Institute of Aeronautics and Astronautics Inc., 2020-08-03)A mechanics-based modeling approach is developed to rapidly predict damage in polymer matrix composites resulting from a low-velocity impact event. The approach is incorporated into a computer code that provides an efficient ... -
Mechanics-based modeling approach for rapid prediction of low velocity impact damage in composite laminates
(merican Institute of Aeronautics and Astronautics Inc, 2020-01-05)A mechanics-based modeling approach is developed to rapidly predict damage in polymer matrix composites resulting from a low velocity impact event. The approach is incorporated into a computer code that provides an efficient ... -
A micro-macro coupling and physics informed modeling approach for bearing failure with x-ray CT characterization
(AIAA SCITECH, 2022-01-03)The failure mechanism of composite bolted joints was investigated using an in-situ X-ray CT technique with SSB test. A physics-informed modeling approach was proposed based on the traditional CDM method and a static bearing ... -
Multi-scale characterization of an adhesive bondline with fabrication induced defects
(DEStech Publications, Inc., 2015)A multiscale characterization of an adhesive bondline is performed to investigate the fabrication defects dependent failure mechanisms of an I-beam under four point bending. To obtain a realistic representative volume of ... -
Multiaxial fatigue damage assessment of repaired composite cruciform specimens using stress ratio dependent fatigue damage accumulation model
(American Institute of Aeronautics and Astronautics, Inc., 2021-12-29)The paper presents a combined experimental and numerical study of multiaxial fatigue damage accumulation in scarf-repaired cruciform specimens subjected to fatigue loading. The existing fatigue analysis module is improved ... -
Numerical studies on buckling and post-buckling behavior of stiffened curved composite panel with repairs
(DEStech Publications, 2019-09)Composite stiffened panels are widely employed in the aircraft industry. In particular, curved panels stiffened with hat-stringers are utilized in fuselages. The panels comprise of very thin skin to which stringers are ... -
Parasitic effects of including microwire sensor tube on in-plane compressive strength of carbon-fiber reinforced polymeric composite laminates
(DEStech Publications, 2019-09)The influence of embedding a titanium alloy sensor tube in carbon fiber-reinforced polymer (CFRP) composite laminates on the in-plane compressive strength has been presented. These sensor tubes cause geometric disturbances ...