NIAR Research Publications
Recent Submissions
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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 ... -
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 ... -
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 ... -
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 ... -
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 ... -
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 ... -
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) ... -
Skin/stringer interface damage characterization of stiffened composite structures
(DEStech Publications, 2021-09-01)With stiffened composite panels being widely used in aerostructures, critical failure mechanics of the skin/stringer interface need to be thoroughly understood. The interface is design critical and must demonstrate the ... -
Coupon-level mechanical testing for polymer-based additive manufacturing
(ASTM International, 2020-06-04)The term additive manufacturing (AM) is used to describe processes of joining materials to make parts from a three-dimensional model data, as opposed to subtractive manufacturing. Although AM technology offers potential ... -
Additive manufactured polymer test coupons: Issues and solutions
(ASTM International, 2020-06-04)Leveraging the experience and lessons learned from the National Center for Advanced Material Performance (NCAMP) and the Composite Materials Handbook-17 (CMH-17) composite material databases, a new qualification program ... -
A combined X-Ray CT and mechanistic characterization of bearing failure mechanisms in bolted composite components
(Vertical Flight Society, 2021-05)This paper presents the characterization of bearing failure mechanisms in composite joints with countersunk bolt by applying an X-ray Computed Tomography (XCT) technique and a developed bearing failure model to build the ... -
Progressive damage mechanisms in thick 3D composites structures under static and fatigue loading
(DEStech Publications, 2020-09)The objective of this work is to demonstrate validation of predictive capabilities capturing both damage initiation and growth under static and fatigue loading in geometrically complex three-dimensional (3D) composite ... -
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 ... -
Compressive response of composite laminates with defects
(American Institute of Aeronautics and Astronautics Inc, 2020-01-05)Defects are inevitable in the manufacture and service of composite laminates and their influence on the mechanical performance of composite laminates can be substantial. Ply waviness and delamination are two major types ... -
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 ... -
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 ... -
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 ... -
A case for Tsai's Modulus, an invariant-based approach to stiffness
(Elsevier, 2020-11-15)For the past six years, we have been benefiting from the discovery by Tsai and Melo (2014) that the trace of the plane stress stiffness matrix (tr(Q)) of an orthotropic composite is a fundamental and powerful scaling ... -
Crack length correction and root rotation angle in a sandwich single cantilever beam (SCB) fracture specimen
(KeAi Publishing Communications Ltd, 2020-12)Crack root rotation is a measure of deviation from clamped boundary conditions of region in front of the crack tip. The root rotation depends on the shear force and bending moment acting at the crack tip. Such rotation ... -
Automated fiber placement (AFP)—Effects of features and defects
(DEStech Publications, 2019)Automated Fiber Placement (AFP) manufacturing methods, considered to be one of the most advanced methods of composite manufacturing, are used in fabricating complex and large scale composite structures. During AFP ...
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