In this study; first of all,
finite element undamped modal analysis was performed on one of the automotive
rear lamp lenses and were obtained natural frequencies and mode shapes. Then,
Frequency Response Functions (FRF) of an automotive rear lamp lens, made of
polymethyl methacrylate (PMMA) material, were obtained by using Impact Hammer
Test Methods. At the same time; dynamic characteristics of the structure,
natural frequencies, damping ratios and mode shapes were obtained. Damping
ratios were calculated from the FRF’s by using the Half Power Method. Finite
Element Analysis (FEA) results and test results were compared and the best test
method was determined.
In this study; the weight of
the modal accelerometer used in the Roving Hammer Impact Test Method was added
in the finite element analysis (FEA) and the undamped modal analysis of the
automotive rear lamp lenses were performed. Also, calculated new Elastic Modulus
for Polymethylmethacrylate (PMMA) material with using
natural frequency formula and this value was used in the ANSYS WB program and the
undamped modal analysis was repeated. After that, frequency response functions (FRFs)
of an automotive rear lamp lens were obtained by using Roving Hammer Impact
Test Method. At the same time; dynamic characteristics of the structure,
natural frequencies, damping ratios and mode shapes were obtained. Damping
ratios were calculated from the FRF’s by using the Half Power Method. Finally, experimental modal analysis (EMA) and
FEA results were compared.
In this study, Random and Harmonic vibration durability test specifications for Automotive Lighting systems are compared according to their damage content. Harmonic and Random vibration durability test specifications which have different durations and Acceleration Power Spectrum Densities (PSD G) are plotted and compared according to damage accumulated on single degree of freedom (SDOF) system. Outcome of this study is the fast evaluation of fatigue strength of common or similar parts used on lighting systems which are dedicated to different customers, different car segments; and evaluation of the severity of new customer vibration durability test specifications and evaluation of special design precautions for new design projects. Shorter duration PSD G's and Harmonic sweep tests which have equivalent Fatigue Damage Spectrums (FDS) can be created and instant design improvements can be tested and evaluated. In addition, in this study, random test time reduction formula was validated with physical tests.
Funding Acknowledgements
Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Spanish Society of Cardiology
Background
There are limited data about the impact of cardiac resynchronization therapy (CRT) in adults with congenital heart disease (CHD) with conflicting results in patients (P) with systemic right ventricle (SRV).
Objectives
We analyzed the one-year outcomes of adults with CHD implanted with CRT and the impact of CRT in P with SRV as compared with systemic left ventricle (SLV).
Methods
Data were analyzed from the Spanish Registry of CRT in adults with CHD (RETRACCA). This is an observational, ambispective (66 % retrospective), multicenter Registry, including 74 adults with CHD implanted with a CRT device from 6 Spanish centers from 2007 to 2021. Ventricular function was assessed by echocardiography and graded on a four-point ordinal scale. Response to CRT was defined as an improvement in NYHA functional class and/or systemic ventricular ejection fraction by at least one category. In addition to changes in functional class and ventricular function, other outcomes analyzed included mortality, heart transplantation and CRT-related complications.
Results
68 P completed one year of follow-up. Table 1 shows the baseline characteristics of the P prior to CRT. The two main indications for CRT were depressed systolic function of the systemic ventricle with more than 40 % ventricular pacing (69 %) and severely depressed systolic function of systemic ventricle, NYHA FC II-IV and QRS > 150 (18 %). Sixty percent of P received a CRT-ICD, whereas 40 % received a CRT-pacemaker. The approach for CRT system implantation was transvenous in 70 % of the patients, mixed in 21 % and fully epicardial in 9 %. Overall, 43 out of 68 patients (75 %) responded to CRT either by improvement of NYHA FC (56 %) and/or systemic ventricular function (41 %). Compared with baseline, CRT was associated with significant improvement in NYHA FC (p<0.001; figure 1), QRS duration (169±31 vs 150±29; p=0.005), and systemic ventricle systolic function (severe or moderate 80 % vs 58 %; p=0.04). Percentage of responders was similar among patients with a SLV (73 %) and with SRV (81 %; p=0.51). Only pre-implant NYHA FC III-IV was predictive of a positive response in the univariate analysis (OR 3.82; 95 % CI 1.03-14.18). Seven complications occurred at implant (10 %). During the follow-up, there were 8 complications in 7 P: 2 P had heart transplantation, 3 P required hospital admission for decompensation of heart failure, 2 P presented pocket infections and 1 lead malfunction. No differences in complication rates were observed between the systemic LV and systemic RV subgroups.
Conclusions
In this series, at one-year follow-up, CRT resulted in improvement in functional class and/or systemic ventricular function in 75 % of P with adult CHD. The percentages of responders and complications were similar among patients with SLV or SRV.
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