1)Fatigue Strength(old) (01.04.2011 17:43)
The
fatigue process consists of three stages: initial fatigue damage
leading to crack nucleation and crack initiation in regions where the
strain is most severe, progressive growth of the crack (crack
propagation) and finally sudden fracture of the remaining cross-section
[44]. Czyryca [45] states that many testing devices and specimen designs
are available for fatigue testing according to the mode of loading:
direct (axial) stress, plane bending, rotating beam, alternating torsion
or combined stress. The selected loading mode should replicate, as
accurately as possible, the actual service condition of the sample being
tested.(Davim. J. P., Machining of Hard Materials, 2011, p. 136-137)
Fatigue strength(new-better) (material properties)
It is well known that there are three major fatigue fracture modes for the high-strength steels. The first one is the fatigue fracture due to crystallographic slip caused by surface roughness or other inhomogeneities. This fatigue fracture is basically observed under low cycle fatigue, normally less than 105
cycles. The second one is caused mainly by non-metallic inclusion, and
no GBF can be clearly observed on the fracture surface. The fatigue life varies usually from 105 cycles to 107
cycles. The third one is also caused by non-metallic inclusion.
Contrary to the second fracture mode, a GBF can be clearly observed on
the fracture surface. The fatigue life is usually beyond 107 cycles. These three fatigue fracture modes are competing in nature.
From the classification above, there may be three fatiguestrengths in correspondence with three fatigue fracture modes.
a. Fatiguestrength determined by surface roughness
The upper bound for fatiguestrength of high-strength steels may be 1.6Hv as suggested by Murakami [39]. However, high-strength
steels usually have very high sensitivity to surface defects, such as
surface scratches, and machining marks, which roughen the surface.
Murakami and Endo [40] proposed a 
parameter model for the prediction of the fatigue limit of specimens with small defects and applied this model to the specimens with artificial surface roughness [41]. For more details, see Refs. [41] and [42]. In this study, the attention was paid to the effect of inclusion on fatigue behavior in the VHCF regime.
parameter model for the prediction of the fatigue limit of specimens with small defects and applied this model to the specimens with artificial surface roughness [41]. For more details, see Refs. [41] and [42]. In this study, the attention was paid to the effect of inclusion on fatigue behavior in the VHCF regime.b. Fatiguestrength determined by internal inclusion
Murakami and Endo [40] proposed the following equation for the prediction of the fatigue limit of specimens with internal inclusion in the high cycle fatigue regime.
(1)
,
in μm, is the square root of the inclusion projected area perpendicular
to the applied stress axis. This equation received much attention due
to its effectiveness and simplicity. Eq. (1) was proposed based on the theoretical consideration and experimental data obtained on the high cycle fatigue testing, therefore the equation is effectiveness to predict the fatiguestrength of high-strength steels at 107 cycles.
Recently, the threshold value of internal small crack is given by an empirical expression for high-strength steels [16].
(2)
(3)
is in meter.
Combining Eqs. (2) and (3) with KImax=Kth and pay attention to the units of crack size in these two equations, the fatiguestrength of specimens with internal inclusion can be expressed as:
(4)
The nomenclatures share the same meaning with Eq. (1).
From the deducing process above, it is noticed that the effect of
hydrogen on formation of GBF is not fully considered. At here, Eq. (4)
could be the critical stress amplitude for just forming GBF. When the
applied stress amplitude is lower than the critical stress amplitude,
the assistant of hydrogen is needed and the GBF will form; otherwise the
GBF will not form. Therefore Eq. (4) is assumed for predicting the fatiguestrength of high-strength steel determined by internal inclusions when the GBF just starts to appear. Refs. [43] reported that the transition of internal fatigue mode from I-mode (internal failure without GBF) to IG-mode (internal failure with GBF) begins at 106 cycles. Table 3 also confirms that the GBF starts to show up when the number of cycles to failure is around 106. Therefore 
could be the fatiguestrength at 106 cycles. Fig. 4 shows that the normalized stress amplitude (
) is about 1 when the fatigue life is around 106 cycles, which further confirms our assumption that 
could be the fatiguestrength at 106 cycles.
could be the fatiguestrength at 106 cycles. Fig. 4 shows that the normalized stress amplitude () is about 1 when the fatigue life is around 106 cycles, which further confirms our assumption that could be the fatiguestrength at 106 cycles.- Table 3. The minimum number of cycles when the GBF shows up in high-strength steels.
Material Number of cycles when the GBF shows up References SUJ2 4.7 × 105 [37] SNCM439 6.2 × 105 [37] SUJ2 1.7 × 106 [10] SCM435 1.1 × 106 [10] SUJ2 3.7 × 105 [18] SUJ2 8.5 × 105 [21] SUJ2 1.6 × 106 [24] QT2000 1.1 × 106 [27] SCM440 1.4 × 106 [44]
- Fig. 4. Relationship between the ratios of stress amplitude over estimated fatiguestrength by Eq. (4), vs. the number of cycles to failure, Nf. (See above-mentioned references for further information.)
c. Fatiguestrength determined by GBF
In our previous study [17], an expression, based on the understanding of the effect of hydrogen during forming GBF, was developed to predict the fatiguestrength of high-strength steels in the very high cycle regime.
(5)
The expression was supported by the fatigue test of 18 kinds of high-strength steel specimens with different inclusion sizes, ultimate tensile strength
ranging from 1680 MPa to 2180 MPa. The predictions and the experimental
results are basically within 20% error band when the inclusion size is
greater than 3 μm. For specimens with inclusion size greater than 6 μm,
the error is basically less than 15%. Since Eq. (5) was proposed and verified based on the fatigue data at 109 cycles, 
should be the fatiguestrength of high-strength steels at 109 cycles.
should be the fatiguestrength of high-strength steels at 109 cycles.
(International Journal of Fatigue, Volume 32, Issue 8, August 2010, page: 1352-1354)
3) Design for High-Temperature Applications(new) (material applications)
THERE IS NO OLDER DEFINITION
A new conceptual framework involving an integrated approach to materials development, component design and life prediction for high-temperatureapplications is outlined. Termed ‘Design for Performance’, this provides an alternative to the traditional approach which requires the creep to rupture testing of many specimens over long periods. Accelerated development of new alloys for higher-temperature turbine blades and discs, and assessment of remaining life of operating components, is now possible. The tests described are a refined stress relaxation test — from which extensive stress versus strain-rate data may be generated over a range of temperatures — and a constant displacement rate crack growth test. These tests provide a separation of the creep strength and fracture resistance criteria required in design. Extensive studies on the cast alloy IN738 have shown that the creep strength is quite insensitive to prior exposure and microstructure, but fracture resistance is very sensitive to thermal history. Relative to the standard heat treatment, fracture resistance can be seriously impaired or substantially improved. It is also shown that calibration with traditional design methods for creep strength is possible. Once minimum performance standards have been established for the original design, these may be used as a basis for life management. For example, decisions regarding component replacement, repair or refurbishment may be made as one or more of these minimum performance standards are approached during service. Thus, the methodology provides a consistent basis for life management for both new and serviced components. It is argued that not only is this approach much faster, more efficient and less costly, but that the framework on which it is based is technically superior to the traditional approach.
(Materials & Design, Volume 14, Issue 4, August 1993, page: 231)
4) Corrective action and preventive action ( CAPA) (new) (process improvement)
THERE IS NO OLDER DEFINITION
Recognized principles of quality management include a component for process improvement, comprised largely of corrective and preventive action taken in response to identified problems. The importance of identifying and investigating problems has been clearly established in transfusion medicine. Such problems can be identified in the following ways: error, incident, and accident reports; adverse reaction reports; customer complaints; process indicator measurements; results of proficiency testing; and results of internal or external audits, inspections, or assessments. Responses to reported events can be remedial, in which the symptom is addressed, or corrective, in which the underlying cause is addressed with the intent to prevent recurrence. If identified problems or their root causes are trended to look for patterns or problems not yet occurring are anticipated, the action taken is proactive and considered preventive. Methods to trend events, monitor processes, and perform root cause analysis are discussed as well as use of the following process improvement `tools': control charts, flowcharting, the `repetitive why', cause-and-effect diagram, and Pareto analysis.
(Transfusion Science, Volume 21, Issue 2, October 1999, Page: 163)
5) Absolute viscosity ( CAPA) (new) (material properties)
THERE IS NO OLDER DEFINITION
The absolute viscosities of lead, thallium and seven lead-thallium alloys were measured as a function of temperature between the liquidus and 500 °C by an oscillating cup viscometer. The viscosity of pure lead ranged from 2.523 cP at 328.5 °C to 1.833 cP at 500.5 °C. The viscosity of pure thallium ranged from 2.600 cP at 303.5 °C to 1.708 cP at 500 °C. A plot of log η versus
was linear for all the samples studied. Isotherms of viscosityversus composition showed a broad maximum in the viscosity
in the vicinity of the composition of maximum liquidus temperature
(37.5 at.% Pb). The maximum appears to shift towards the equiatomic
composition at higher temperatures where it becomes more diffuse. These
results support the belief that certain liquid alloy solutions contain
molecular-type aggregates or “clusters”, the stoichiometries of which
are subject to a temperature-dependent dissociation reaction.
Furthermore, the results support some previous reports that the
composition range 12.5 – 100 at.% Pb is not a continuous primary solid
solution, but may be interrupted by an intermediate phase or phases.
2) Separable Connection: 24.03.2011 01.07 (old)
Separable connections are
designed to permit disassembly and reassembly; they are meant to be
connected and disconnected multiple times. When connected they must provide metal-to-metal contact between mating components with high reliability and low electrical resistance. Separable connection devices are called connectors and they come in a variety of styles to serve many different applications. Connectors typically consist of multiple contacts, contained in a plastic molded housing, designed to mate with a
compatible connector or with individual wires or terminals. They are
used for making electrical connections between various combinations of
cables, printed circuit boards, components, and individual wires.
A wide selection of connectors is available. The design issues in choosing among them include power level (e.g., whether the connector is used for power or signal transmission), cost, number of individual conductors involved, types of devices and circuits to be connected, space limitations, ease of joining the connector to its leads, ease of connection with the mating terminal or connector, and frequency of connection and disconnection. Some of the principal connector types are cable connectors, terminal blocks, sockets, and connectors with low or zero insertion force.
(Mikell P. Groover,Fundamentals of Modern Manufacturing,4th Edition,pg.851-852)
Separable Connection (new-better) (Connection)
An advatage of a two-part connector is that the
vendor supplying the two mating connector
parts has control over both of the mating surfaces of the seperable contact
and of the alignment mechanism.This shouId lead to consistency and
accuracy, which may not otherwise be possible. There may, however, be
cost penalties both in the connector itself and in the cost of assembling
the parts.
lmplicit in the requirement for a separable connection, the connector
system must also have the following capabilities:
*Fit the elements to be connected
*Align the elements
*Actuate the connection
*Satisfy the performance specifications
*Resist the forces which could degrade the connection
*Permit contact seperation when required
*Survive in good operating older for the product life
(Microelectronics Packaging Handbook: Subsystem packaging, Rao R. Tummala,Eugene J. Rymaszewski,Alan G. Klopfenstein, 1997, page: 398)
parts has control over both of the mating surfaces of the seperable contact
and of the alignment mechanism.This shouId lead to consistency and
accuracy, which may not otherwise be possible. There may, however, be
cost penalties both in the connector itself and in the cost of assembling
the parts.
lmplicit in the requirement for a separable connection, the connector
system must also have the following capabilities:
*Fit the elements to be connected
*Align the elements
*Actuate the connection
*Satisfy the performance specifications
*Resist the forces which could degrade the connection
*Permit contact seperation when required
*Survive in good operating older for the product life
(Microelectronics Packaging Handbook: Subsystem packaging, Rao R. Tummala,Eugene J. Rymaszewski,Alan G. Klopfenstein, 1997, page: 398)
3) Design for High-Temperature Applications(new) (material applications)
THERE IS NO OLDER DEFINITION
A new conceptual framework involving an integrated approach to materials development, component design and life prediction for high-temperatureapplications is outlined. Termed ‘Design for Performance’, this provides an alternative to the traditional approach which requires the creep to rupture testing of many specimens over long periods. Accelerated development of new alloys for higher-temperature turbine blades and discs, and assessment of remaining life of operating components, is now possible. The tests described are a refined stress relaxation test — from which extensive stress versus strain-rate data may be generated over a range of temperatures — and a constant displacement rate crack growth test. These tests provide a separation of the creep strength and fracture resistance criteria required in design. Extensive studies on the cast alloy IN738 have shown that the creep strength is quite insensitive to prior exposure and microstructure, but fracture resistance is very sensitive to thermal history. Relative to the standard heat treatment, fracture resistance can be seriously impaired or substantially improved. It is also shown that calibration with traditional design methods for creep strength is possible. Once minimum performance standards have been established for the original design, these may be used as a basis for life management. For example, decisions regarding component replacement, repair or refurbishment may be made as one or more of these minimum performance standards are approached during service. Thus, the methodology provides a consistent basis for life management for both new and serviced components. It is argued that not only is this approach much faster, more efficient and less costly, but that the framework on which it is based is technically superior to the traditional approach.
(Materials & Design, Volume 14, Issue 4, August 1993, page: 231)
4) Corrective action and preventive action ( CAPA) (new) (process improvement)
THERE IS NO OLDER DEFINITION
Recognized principles of quality management include a component for process improvement, comprised largely of corrective and preventive action taken in response to identified problems. The importance of identifying and investigating problems has been clearly established in transfusion medicine. Such problems can be identified in the following ways: error, incident, and accident reports; adverse reaction reports; customer complaints; process indicator measurements; results of proficiency testing; and results of internal or external audits, inspections, or assessments. Responses to reported events can be remedial, in which the symptom is addressed, or corrective, in which the underlying cause is addressed with the intent to prevent recurrence. If identified problems or their root causes are trended to look for patterns or problems not yet occurring are anticipated, the action taken is proactive and considered preventive. Methods to trend events, monitor processes, and perform root cause analysis are discussed as well as use of the following process improvement `tools': control charts, flowcharting, the `repetitive why', cause-and-effect diagram, and Pareto analysis.
(Transfusion Science, Volume 21, Issue 2, October 1999, Page: 163)
5) Absolute viscosity ( CAPA) (new) (material properties)
THERE IS NO OLDER DEFINITION
The absolute viscosities of lead, thallium and seven lead-thallium alloys were measured as a function of temperature between the liquidus and 500 °C by an oscillating cup viscometer. The viscosity of pure lead ranged from 2.523 cP at 328.5 °C to 1.833 cP at 500.5 °C. The viscosity of pure thallium ranged from 2.600 cP at 303.5 °C to 1.708 cP at 500 °C. A plot of log η versus
was linear for all the samples studied. Isotherms of viscosityversus composition showed a broad maximum in the viscosity
in the vicinity of the composition of maximum liquidus temperature
(37.5 at.% Pb). The maximum appears to shift towards the equiatomic
composition at higher temperatures where it becomes more diffuse. These
results support the belief that certain liquid alloy solutions contain
molecular-type aggregates or “clusters”, the stoichiometries of which
are subject to a temperature-dependent dissociation reaction.
Furthermore, the results support some previous reports that the
composition range 12.5 – 100 at.% Pb is not a continuous primary solid
solution, but may be interrupted by an intermediate phase or phases.
(Journal of the Less Common Metals, Volume 64, Issue 1, March 1979, Pages 135)
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