Failing point of a lexan spheres?

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SUMMARY

The discussion centers on the structural integrity and buoyancy calculations for 2500mm and 3000mm lexan spheres with a thickness of 50mm submerged in seawater. Key calculations include the depth of submersion before implosion, drop height onto water, and the weight required for neutral buoyancy. Mechanical properties of lexan, such as tensile and flexural stress and strain, are provided, emphasizing the need for professional engineering assistance due to the potential life-safety implications of the project.

PREREQUISITES
  • Understanding of tensile and flexural stress and strain in materials
  • Knowledge of buoyancy principles and calculations
  • Familiarity with impact resistance testing methods
  • Basic principles of fluid mechanics, particularly related to submerged objects
NEXT STEPS
  • Research "Lexan plastic mechanical properties" for detailed material behavior
  • Study "Buoyancy calculations for submerged objects" to understand neutral buoyancy
  • Learn about "Impact resistance testing standards" for lexan materials
  • Investigate "Professional engineering services for safety-critical projects" for guidance
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Engineers, material scientists, and project managers involved in safety-critical applications, particularly those working with buoyancy and impact resistance of plastic materials.

aussie101
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Hi
I'm a newby and have a project way out of my depth where a wrong calculation will be fatal...

I need calculations of :

1.how far a 2500mm and 3000mm sphere of lexan plastic 50mm thick can be submerged in sea water before it will implode/fail (in meters)? See data below.

2.From what height can the either sphere be dropped from onto the sea water surface tension before failing?

3.How much weight (kg) would it take to make the spheres neutrally buoyant (neither sink or float)?

4.Can the stress formed in process (inside the sphere) be calculated and ratio to the above calcs? (e.g. For every mpa stress in structure will reduce the mpa of impak or pressure resistance/rating)

MECHANICAL
Tensile Stress, yld, Type I, 50 mm/min 590 kgf/cm²
Tensile Stress, brk, Type I, 50 mm/min 580 kgf/cm²
Tensile Strain, yld, Type I, 50 mm/min 5.7 %
Tensile Strain, brk, Type I, 50 mm/min 117.9 %
Tensile Modulus, 50 mm/min 23000 kgf/cm²
Flexural Stress, yld, 1.3 mm/min, 50 mm span 960 kgf/cm²
Flexural Modulus, 1.3 mm/min, 50 mm span 22900 kgf/cm²
Tensile Stress, yield, 50 mm/min 57 MPa
Tensile Stress, break, 50 mm/min 56 MPa
Tensile Strain, yield, 50 mm/min 5.4 %
Tensile Strain, break, 50 mm/min 119.4 %
Tensile Modulus, 1 mm/min 2340 MPa
Flexural Stress, yield, 2 mm/min 89 MPa
Flexural Modulus, 2 mm/min 2140 MPa
IMPACT
Izod Impact, notched, 23°C 75 cm-kgf/cm
Izod Impact, notched, -30°C 63 cm-kgf/cm
Instrumented Impact Total Energy, 23°C 763 cm-kgf
Izod Impact, notched 80*10*4 +23°C 47 kJ/m²
Izod Impact, notched 80*10*4 -30°C 24 kJ/m²
Charpy 23°C, V-notch Edgew 80*10*4 sp=62mm 61 kJ/m²
Charpy -30°C, V-notch Edgew 80*10*4 sp=62mm 17 kJ/m²
 
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You are not going to get help here with projects that could have life-safety implications. You need to engage a professional engineer to help with projects like that.

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