Có 20+ tài liệu thuộc chủ đề "kỹ thuật chế tạo"
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Tƣơng tác xếp chồng điện tử π trong tinh thể phân tử hữu cơ. Cấu trúc phân tử của vật liệu bán dẫn hữu cơ MPc dựa trên tính toán DFT và thực nghiệm. Cấu trúc phân tử và phổ IR của ZnPc. Cấu trúc phân tử và phổ IR của CuPc. Cấu trúc điện tử của tinh thể β-MPc...
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Thiết kế quy trỡnh cụng nghệ gia cụng chi tiết thõn thủy lực. Phõn tớch chức năng làm việc của chi tiết:. Phõn tớch tớnh cụng nghệ trong kết cấu của chi tiết:. Đề tài: Thiết kế quy trỡnh cụng nghệ gia cụng chi tiết thõn thủy lực.. Trờn đú cú cỏc mặt phẳng phải gia cụng với độ chớnh...
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Thiết kế vật đúc. Chọn vị trí vật đúc trong khuôn rót:. của vật đúc.. thành vật đúc- thiết kế chuyển tiếp thành vật đúc. Giữa các thành vật đúc có phần chuyển tiếp. Sai lệch cho phép về kích th-ớc, khối l-ợng của vật đúc và l-ợng d-:. Bảng B5 – sai lệch cho phép về khối l-ợng của...
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Ba điện cực số 2 (Số điện cực theo số pha của dòng điện);. Giá điện cực 1 và cơ cấu quay nghiêng lò;. Cơ cấu di chuyển thân lò hay hỏng hóc.. đẩy các cơ cấu khác…. Điện cực được kẹp chặt vào giá điện cực bằng cơ cấu lò xo và nới lỏng bằng xilanh khí nén.. Trên...
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,"". 1 IE6 €•‚". K y ? C • ~V y ed • d"dOd y ed"dOd. A2 x+l • C % 4Q ` Z. y d"dOe • d"dxl y d"d_x. O"x ". Q"". Q""0. d"O d"x. d"s d"_. "O x"l. "O x"l ) 0. S 6L 0 0T /6) R … R ". y x"N O ∆p". E ' 2...
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The stress intensity factor solution of Raju and Newman [13] for surface cracked smooth bars is utilized, and assumptions are made concerning the geometry of the crack such that the stress intensity factor may be approximated as. (I.5) where a is the crack depth and D is the diameter of the bar. Due to the presence of the notch, the...
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High Cycle Fatigue. Tables of contents may be reproduced for internal circulation, but permission of the Publisher is required for external resale or distribution of such material. Permission of the Publisher is required for all other derivative works, including compilations and translations.. Permission of the Publisher is required to store or use electronically any material contained in this work, including...
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The first question a prospective reader or purchaser of this book may ask is, “Why another book on fatigue?” This is a very legitimate question because there are many books and hundreds of journal articles dealing with various aspects of fatigue, including high cycle fatigue (HCF). In fact, in researching various aspects of HCF, the author was drawn back in...
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The Engine Structural Integrity Program (ENSIP) handbook (MIL-HDBK-1783A dated 22 Mar 99. Many mechanical, electronic and software problems are identified and corrected in the EMD program. At the end of the EMD program, a review of the analyses and test reports validates the functional requirements.. Two of the challenges of the development program, which affect reliability of the field engine,...
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as a knowledge of the vibratory loading, is a viable and reliable method for designing for pure HCF. The problem appears to be the synergistic combination of HCF with other modes of initial or service-induced damage, something that is not addressed in a Goodman diagram. As noted earlier, the HCF problem in turbine engines provides an example of how HCF...
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Incidents such as these bring to mind the words of the famous detective Sherlock Holmes who said. Hopefully, the information contained within this book will add to the understanding of many of the aspects of high cycle fatigue material behavior.. Crouch, J.O., “Air Force Turbine Engine Reliability”, presented at the NAS Committee of National Statistics Sponsored Reliability Workshop, Washington, DC,...
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A schematic diagram of S–N data, obtained at different values of R = constant, is presented as Figure 2.11. In Figure 2.11, the stress is plotted as the maximum stress although the stress range or alternating stress could also be used. Each of the data points can then be used in a constant life plot such as a Haigh diagram...
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Figure 2.22. Alternating stress/ultimate stress. Mean stress/ultimate stress. Figure 2.23. 0 plotted on a Haigh diagram.. While there seemed to be a physical basis of some sort for all of the approaches, combined with simplicity, it should be pointed out that the choices of methods of representing data were scrutinized throughout their development. Commenting on the W–L formula, used to...
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Figure 2.30. Because of the large number of terms, most experimentally determined constant life data may be represented by proper selection of the constants.. JASPER EQUATION. For purely uniaxial loading, the shaded area in Figure 2.31 illustrates schematically the stored energy for the cases where loading is purely tensile R >. 0, which involves tension and compression in a single...
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Figure 2.40. It is only when the crack driving force due to positive stresses only, pos , exceeds the threshold that the crack will continue to grow. An alternate and more plausible explanation, without any direct evidence, is that the stress intensity needed to propagate an existing crack becomes smaller as the amount of compression increases. that LCF cycling at...
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Schematic of step-loading procedure.. others do not because the test is terminated after a large number of cycles (run-out). Another justification for a non-constant load to determine the fatigue limit is, as Prot [14] points out, “in practice, fatigue loads are not regularly variable, but they are not uniform amplitude loads.”. One of the main concerns in establishing material allowables...
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Figure 3.16. Comparison of number of cycles in last loading block of step test for HCF with and without LCF precrack.. Additional data are available on the number of cycles on the last loading block in the step-loading tests when a crack is present. The data of Figure 3.16 are supplemented with additional data on precracked notch specimens and replotted...
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is discussed based on experimental observations of the type that are classified as all-or- nothing or quantal. While it is generally desirable to have quantitative measurements, many cases can be expressed only as “occurring” or “not-occurring.” The obvious example with insects is death. The analogous situation with FLSs, especially those obtained from staircase type testing, is failure or survival (run-outs)...
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that random construction of a staircase sequence will provide similar results, particularly for the mean value of the FLS.. In this artificial staircase procedure using the bootstrap method, every data point was treated in one of the following three manners and every data point was used once:. If a specimen failed within 10 9 cycles at a given stress level,...
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predictions, the RFL model, described above, was used. The RFL model treats run-out and failure tests with 2D scatter in both life (LCF regime) and the endurance stress (HCF regime). An advantage of the RFL model is that the 1D scatter assumptions are not required. The RFL model predictions with the baseline + step or staircase results are given in...