Determination and Validation of Residual Stresses in CFRP/Metal Hybrid Components Using the Incremental Hole Drilling Method

Tinkloh, Steffen Rainer; Tröster, Thomas; Zinn, Wolfgang; Niendorf, Т.

doi:10.3390/jcs4030143

Cited by 13 publications

(27 citation statements)

References 24 publications

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“…Even though this method may not assess stresses as deeply as the slitting method, its convenient practical implementation and available standardized testing procedure make it a method of choice over other ones. [59,60] A schematic of clockwise strain gauge rosettes in this method is shown in Figure 5. The positive x-direction lies along the axis of gauge 1, and the negative y-direction lies along the axis of gauge 3, and a circular hole is drilled at the center of that.…”

Section: Hole Drilling Methodsmentioning

confidence: 99%

Residual Stress in Engineering Materials: A Review

et al. 2021

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The accurate determination of residual stresses has a crucial role in understanding the complex interactions between microstructure, mechanical state, mode(s) of failure, and structural integrity. Moreover, the residual stress management concept contributes to industrial applications, aiming to improve the product's service performance and life cycle. In this regard, the industry requests rapid, efficient, and modern methods to identify and control the residual stress state. This review article contains three main sections. The first section covers different residual stress determination methods and reports the advancements over the recent decade. The second section includes the role of residual stresses in the performance of a broad range of materials including metallic alloys, polymers, ceramics, composites, and biomaterials. This is presented by classifying different science areas dealing with residual stresses into two main groups, including “origins” and “effects” of residual stresses. The range of topics covered are “welding, machining, curing/cooling, and spray coating processes,” “medical and dental sciences,” and “fatigue and fracture mechanisms.” The third section summarizes various strategies to effectively control residual stresses through different manufacturing procedures. It is hoped that the data provided herein serves as a valuable up‐to‐date reference for engineers and scientists in the field of residual stress.

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Section: Hole Drilling Methodsmentioning

confidence: 99%

Residual Stress in Engineering Materials: A Review

et al. 2021

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“…For measuring the residual stresses in FRP, the strain gauges 1 and 5 were always aligned with the fiber direction X. The impact of the misalignment of the strain gauge on the resulting residual stress was already discussed in [17].…”

Section: Principle Of the Hole Drilling Methods (Hdm)mentioning

confidence: 99%

“…The steel employed was HC340LA (microalloyed steel). Note that the steel sample before hybridization was not curved and heat treated, thus, it features initial residual stresses to a certain degree (the actual value was measured using the HDM and adequate strain gauges (Höttinger Baldwin Messtechnik GmbH, Darmstadt, Germany); see [17] for more details). Here, it is important to note that the initial residual stress values of different metal sheets used for hybridization could be slightly different.…”

Section: Experimental Procedures and Microstructure Characterization 3mentioning

confidence: 99%

“…The HDM was then extended to be able to determine in-depth residual stresses in orthotropic materials by developing a novel evaluation formalism and drilling the hole in a successive manner [13][14][15], where the calibration coefficients were calculated using FEA with a plane element using the integral method, assuming that the stress is uniform in each drilling layer. Very recently, some of the present authors [16,17] applied a brick element in FEA to calculate the calibration coefficients for an improved description of more complex and realistic stress profiles in CFRP and CFRP/steel hybrid composites, where a special strain gauge with eight grids was utilized. Most importantly, by using mechanical bending tests the reliability and accuracy of the residual stress measurement in these samples through HDM was validated [16,17].…”

Section: Introductionmentioning

confidence: 99%

“…Very recently, some of the present authors [16,17] applied a brick element in FEA to calculate the calibration coefficients for an improved description of more complex and realistic stress profiles in CFRP and CFRP/steel hybrid composites, where a special strain gauge with eight grids was utilized. Most importantly, by using mechanical bending tests the reliability and accuracy of the residual stress measurement in these samples through HDM was validated [16,17].…”

Section: Introductionmentioning

confidence: 99%

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Measurement and Analysis of Residual Stresses and Warpage in Fiber Reinforced Plastic and Hybrid Components

Tinkloh

Tröster

Zinn

et al. 2021

Metals

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Glass/carbon fiber reinforced plastic (GFRP/CFRP) and hybrid components have attracted increasing attention in lightweight applications. However, residual stresses induced in the manufacturing process of these components can result in warpage and, eventually, negatively affect the mechanical performance of the composite structures. In the present work, GFRP, CFRP, GFRP/steel and CFRP/steel hybrid components were manufactured through the prepreg-press-technology always employing the same process parameters. The residual stresses of these components were measured through the hole drilling method (HDM), based on an adequate formalism to evaluate the residual stresses for orthotropic materials including the calculation of the calibration coefficients via finite element analysis (FEA). In FEA, the real material lay-up and mechanical properties of the samples were considered. The warpage induced by residual stresses was measured after the samples were removed from the tool. The measured residual stresses and warpage of four different types of samples were compared and results were analyzed in depth. The results obtained can be extended to other hybrid materials and even could be used for designing multi-stable laminates for application in adaptive structures. Moreover, the effects of the drilling process parameters of HDM, e.g., the drilling speed, the drilling increment and the zero-depth setting, on the resulting residual stresses of GFRP were investigated. The reliability of residual stress measurements in GFRP using HDM was validated through mechanical bending tests. The conclusions concerning the choice of optimal drilling parameters for GFRP could be directly applied for other types of samples considered in the present work.

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