| 1. |
|
|
| 2. |
- Hoier, Philipp, 1988, et al.
(författare)
-
On assessing grindability of recycled and ore-based crankshaft steel: an approach combining data analysis with material science
- 2021
-
Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 104, s. 1601-1606
-
Konferensbidrag (refereegranskat)abstract
- Material-related grindability variations when grinding recycled and ore-based steel can significantly impair the process efficiency during finishing of automotive crankshafts. To address this problem and to achieve more robust grinding processes, the underlying causes of variation need to be understood. The present work investigates the feasibility of using quality data obtained during production to study grindability variations and identify material-related effects. Analysis of non-destructive inspection protocols indicates steel supplier-dependent differences in grindability. However, no systematic grindability differences between recycled and ore-based steel could be identified. Possible correlations between grindability and material characteristics obtained from supplied steel certificates are discussed.
|
|
| 3. |
- Gyllenhammar, Daniel, 1994, et al.
(författare)
-
How to facilitate improvements in public service systems: propositions for action
- 2023
-
Ingår i: International Journal of Quality and Reliability Management. - 0265-671X. ; 40:6, s. 1429-1448
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose The purpose of this article is to increase the understanding of how improvements can be facilitated in a public service containing multiple actors in terms of identifying, aligning and prerequisites for the improvements. Design/methodology/approach The research utilizes an interactive research approach where data were gathered though a conference, workshop and a survey. The study alternately combines quality management methods such as affinity and interrelationship diagrams with computer aided text mining and latent semantic analysis. Findings The research shows that practitioners must consider interconnectedness between improvements and benefits that are crossing organizational levels of the public service system as well as professional borders. In public service systems, the complex reality can be better understood when improvements and benefits are classified into different organizational layers and an interconnectedness and sequence of improvement areas are acknowledged. Research limitations/implications The research is set in the Swedish public service of the tax-paid sick leave insurance. Future research would benefit by investigating similar cases in other nations and other services. Practical implications The used methodology can be applied by practitioners to enhance a unified understanding of the system required to improve. The study also guides practitioners for how to support, relive hinders and prioritize improvements. Originality/value The research fills a gap of understanding of improvements in public services with multiple actors. As this area is difficult to improve, a novel combination of qualitative and quantitative methods paved the way for deeper and more unified understanding of the system.
|
|
| 4. |
- Hammersberg, Peter, 1961, et al.
(författare)
-
EMULATION OF POD CURVES FROM SYNTHETIC DATA OF PHASED ARRAY ULTRASOUND TESTING
- 2012
-
Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 1430:31, s. 937-944
-
Konferensbidrag (refereegranskat)abstract
- Reliability of non-destructive techniques (NDT) is traditionally quantified byexperimental determined probability of detection (POD). Such multi-parameter variability studies require a significant amount of experiments for each application verified, making them extremely costly. Reducing the need of experimental data by simulations requires both a verified simulation model and a procedure for effective computer experiments. Here synthetic POD curves for ultrasonic phased array testing have been generated using simSUNDT for signal amplitude simulations and a procedure to emulate response variability by predictive (meta) modeling and Monte Carlo simulations.
|
|
| 5. |
- Hammersberg, Peter, 1961, et al.
(författare)
-
Modelling the Variation of Tensile Properties of High-Silicon Ductile Iron
- 2018
-
Ingår i: 2018 AFS Transactions, American Foundry Society. - 9780874334630 ; 126, s. 155-164
-
Konferensbidrag (refereegranskat)abstract
- For an optimized gating system, the influence of chemical composition can be controlled to a greater extent than in non-optimized conditions, where hidden mechanisms prevail. In this work, GJS-600-10 (EN 1563:2012) solid-solution-strengthened ferritic spheroidal graphite iron with advantageous machinability due to uniform hardness, has been used to elucidate interaction effects and create a material regression model to predict the tensile properties. In this case, key predictors are related to the tensile properties (Rp0,2, Rm, A), of over 120 industrial tensile specimens from 10 years of research. A partial least square (PLS) regression reveals that elements in the steel scrap strongly affect elongation, yield strength and ultimate tensile strength. The analysis reveals that strength to a great extent can be predicted by the chemical composition whereas ductility also depends on other factors.
|
|
| 6. |
- Hammersberg, Peter, 1961-, et al.
(författare)
-
Optimal Computerized Tomography Performance
- 1999
-
Ingår i: Computerized Tomography for Industrial Application and Image Processing in Radiology,1999. ; , s. 31-
-
Konferensbidrag (refereegranskat)
|
|
| 7. |
- Hammersberg, Peter, 1961, et al.
(författare)
-
Proactive control of weld dimensions in robotised MAG welding
- 2013
-
Ingår i: Proceedings of the second Swedish conference on design and fabrication of welded structures.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Keeping all welding dimension on target and within specification limits is a multiparameter optimisation problem that involves trade-offs between potentiallycontradicting requirements. In the fillet weld case study, the balancing act is to keep fillet weld bead thickness on target and simultaneously fulfil a minimum requirementof both weld toe radii and weld penetration of the base material. With a robustengineering approach, consisting of screening, modelling, multi-parameter optimisation and robust assessment, some interesting observations regarding the relationships between welding control parameters and resulting weld dimensions have been made. The parameters that directly influence welding productivity, such asbeam power (U, I), speed and material feed, were found to be of secondary importance for controlling the toe radius, penetration dimensions and the weld bead thickness, compared to the influence of the welding geometry (torch and plate positions). With the multi-parameter model developed, it was possible to predict and verify a setting of the welding geometry that fulfilled all weld dimension specifications simultaneously and to estimate the width of a production window that allows for some control factor variability. This result opens up a new strategy to the development of both welding productivity and quality at the same time, even though it takes some offline response surface modelling (RSM) or on-line evolutionary process (EVOP) experimental procedures, at least for this particular welding scenario: a 5mm fillet welds with at least 2mm penetration and smooth (>1mm) weld toe transition.
|
|
| 8. |
- Hammersberg, Peter, 1961, et al.
(författare)
-
Statistical evaluation of welding quality in production
- 2010
-
Ingår i: Proceedings of the Swedish Conference on Light Weight Optimized Welded Structures. - 1651-7660. - 9789174156089 ; , s. 148-162
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this study the change in pre-conditions for quality/inspection are studied when the performance of an existing robotised welding process is improved using parameter design from robust design methodology. The findings are several. First, it was found that it is possible to build empirical response surface models of the key performance indicators measured that serves to improve the chances to find settings in the welding geometry that fulfil all requirements without increasing production cost. Secondly, it was also found that basic standard gauges and procedures for weld quality inspection easily are out-dated if not care is taken to investigate and improve all measurement systems used relative the actual variations occurring in the production. Thirdly, it was showed that improved welding performance will change pre-conditions for both product development and quality/inspection. Fourthly, ultrasonic P-scan has the potential to monitor penetration depth, but lower detection limits need to be further explored. Ultrasonic time-of-flight deflections his problems to monitor welding penetration depth less than 5mm on the present fillet weld set-up.
|
|
| 9. |
- Hammersberg, Peter, 1961, et al.
(författare)
-
Study of Barkhausen Emission from the Surface Martensite Layer on Induction-hardened Carbon Steel
- 2018
-
Ingår i: 12th European Conference on Non-Destructive Testing (ECNDT 2018), Gothenburg 2018, June 11-15 (ECNDT 2018). ; 2018:08
-
Konferensbidrag (refereegranskat)abstract
- Induction hardening is one of the finishing processes to improve hardness and wear resistance on steel products by developing a hard martensite-rich surface layer. Non-destructive Barkhausen noise (BN) evaluation is used for quality assurance. While the routine production is set to develop a desirable hardening depth of this specific structure, the variations of microstructure and grain size overlay the outbound results in the assessment and make the interpretation unambiguous. This work correlates the different parameters in BN-signal with the deviations from the targeted martensite by predictive, physical and numerical modelling means.
|
|
| 10. |
- Hammersberg, Peter, 1961, et al.
(författare)
-
The Potential in Simulation and Metamodeling for the Understanding and Development of NDE
- 2014
-
Ingår i: Materialpruefung/Materials Testing. - : Walter de Gruyter GmbH. - 0025-5300 .- 2195-8572. ; 56:11-12, s. 980-987
-
Tidskriftsartikel (refereegranskat)abstract
- By combining detailed mathematical modeling of the physics involved in NDE with a broader and robust engineering approach based on the sequential steps of screening, modeling and optimization, it is possible to generate metamodels that can support NDE engineering efforts to evaluate the applicability of NDE in a wider context, as a complement to the repeatability, reproducibility and capability studies normally performed. The aim of the initial screening phase is to effectively evaluate and prioritize NDE control parameters from a wider perspective regarding the demands of a specific application and to prioritize parameters of lesser importance for the outcome on the basis of economic and practical considerations. The aim of the second and third steps is to study the influence of the important parameters and to perform sensitivity analyses of reproducibility and repeatability, for example, followed by procedure development, respectively. The methodology is straightforward when it comes to smooth response surfaces of lower order (up to second or third order). Generally, the recommendation for the screening phase is 'to be bold' for the definition of the experimental range for each parameter - meaning to make them as wide as possibly relevant for the specific application. For NDE applications not following the Berens assumption for POD studies, e. g., large cracks yield large response signals, such as the varying signal amplitudes from surface breaking notches in ultrasonic testing, the mentioned recommendation of. be-bold. screening phase may lead to incorrect prioritization of parameters. In this publication, this is illustrated by how the width of the experimental range for the control parameters tested during screening actually influences the screening results. Two basic ultrasonic testing set-ups have been compared using the SimSUNDT simulation software package: surface breaking notch (SBN) and side drilled hole (SDH). Even though the results were anticipated, they pointed out the need to further develop the screening methodology supporting NDE engineering, especially when it comes to addressing the issue of applicability. Does the data collected tell us what we actually want to know about the tested application? Or does it only tell us something about the NDE method?
|
|
