JC Applied Technology flashcards
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31 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Design iteration loop
- A cycle in which prototypes are tested against stated criteria, results are compared with targets, and the design or the criteria are revised before the next build.
- Functional constraint
- A requirement describing what a design must do or perform, such as lifting a stated load or lasting a stated number of cycles, independent of how it is built.
- Design trade-off
- A compromise in which improving one performance criterion degrades another, resolved by weighting criteria and documenting why the chosen balance was preferred.
- Low-fidelity prototype
- A cheap, quickly built model used to test a single uncertain assumption before investing in detailed design, materials, or manufacturing tooling.
- Root cause analysis
- A structured method, such as repeated why-questions or a cause-and-effect diagram, that traces an observed failure back to the underlying process or design defect.
- FMEA risk priority number
- A ranking computed as severity times occurrence times detection, used to order potential failure modes so the highest-risk items are addressed first.
- Usability test
- Observation of representative users performing realistic tasks, revealing interface errors and confusion that expert inspection alone typically misses.
- Design documentation
- A dated record of version, test conditions, raw measurements, and decisions, sufficient for an uninvolved person to reproduce the result and understand the rationale.
- Measurement uncertainty
- The quantified range within which the true value is expected to lie, combining instrument accuracy, resolution, and variability of repeated readings.
- Resolution versus accuracy
- Resolution is the smallest change an instrument can display; accuracy is how close its reading is to the true value. High resolution does not guarantee accuracy.
- Calibration
- Comparison of an instrument's readings with a traceable reference, producing corrections that document and compensate for systematic deviation from true values.
- Nyquist criterion
- The rule that a signal must be sampled at more than twice its highest frequency component to avoid aliasing, which permanently corrupts the sampled data.
- Aliasing
- A sampling artifact in which high-frequency content appears as a false lower-frequency signal; it cannot be removed by filtering after sampling.
- 4-20 mA current loop
- An analog sensor interface in which the measured value is encoded as loop current, chosen because current is immune to voltage drops along long cables.
- Proportional control
- A control action whose output is proportional to the current error; increasing gain speeds response but too much gain produces oscillation and instability.
- Integral windup
- Accumulation of integral control action while the actuator is saturated, causing large overshoot when the error finally reverses direction.
- Battery runtime estimate
- Runtime equals battery capacity in amp-hours divided by average load current, then reduced to account for temperature effects and converter losses.
- Averaging to reduce noise
- Combining N independent samples lowers random noise by the square root of N, but leaves systematic bias unchanged because bias affects every sample equally.
- Elastic modulus
- The slope of the linear portion of a stress-strain curve, expressing stiffness as stress divided by strain with units of pressure.
- Stress and strain
- Stress is applied force divided by cross-sectional area; strain is change in length divided by original length, so strain is dimensionless.
- Safety factor
- Material failure strength divided by maximum expected service stress, covering load uncertainty, material variability, and the consequences of failure.
- Toughness
- The energy a material absorbs before fracture, represented by the area under the stress-strain curve; high strength alone does not imply high toughness.
- Hardness
- Resistance of a surface to indentation and scratching, used as a selection criterion where wear, abrasion, or contact damage governs service life.
- Galvanic corrosion
- Accelerated attack occurring when two dissimilar metals are joined in the presence of an electrolyte, with the less noble metal corroding preferentially.
- Fastener versus adhesive
- Fasteners permit disassembly and join dissimilar materials; adhesives distribute load across an area but need careful surface preparation and tolerate temperature less well.
- Injection molding
- A high-volume polymer process in which molten material is forced into a steel mold, economical for complex parts once tooling cost is spread over many units.
- Additive manufacturing
- Building a part layer by layer from a digital model, suited to low volumes, one-off prototypes, and internal channels that conventional machining cannot reach.
- Worst-case tolerance stack
- An assembly analysis that sums every component tolerance in the chain, guaranteeing fit but often forcing tighter and more expensive individual tolerances.
- Statistical tolerance stack
- An assembly analysis combining independent tolerances by root-sum-square, giving a tighter predicted variation at the cost of a small risk of interference.
- Life-cycle assessment
- Evaluation of energy, material, and emissions impacts per functional unit across extraction, manufacture, use, and disposal, enabling fair comparison between designs.
- Design for assembly
- Reducing part count, easing handling and orientation, and simplifying fastening so products can be assembled faster with fewer errors and lower cost.