LG G Flex curved smart phone bends but doesn’t break

Not many electronic devices make a claim for their physical flexibility. After all, smart phones, TVs, computers, and tablets are made from rigid plastic and glass, which are more likely to snap or shatter than bend forgivingly. Then along came LG, touting its G Flex as “the world’s first curved, flexible smart phone,” with this important caveat: “The flexibility of this product is limited. This phone may be bent flat up to 180 degrees for a limited period of time only. Do not bend inward or twist.” (See the screen grab from the LG site below.)

Why, we wondered, would anyone need a bendable phone?

The answer is pretty straightforward. It turns out that flexibility may help with durability. The arc of the G Flex acts like a leaf spring, absorbing energy when pressure is applied to the phone, such as when you lean or sit on the phone when it’s lying on a table. LG was initially pretty vague about just how flexible the G Flex is, but when we pressed company representatives for data, we were told that it had been tested at 88 pounds of pressure for 100 repetitions. A specific claim such as that begs for verification, so we checked our labs to see what sort of complicated, expensive equipment we might have that could help us check LG's numbers.

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In our materials testing lab, we found the Instron compression test machine. This large test platform uses computer-controlled motors and “load cells” that are powerful enough to crush concrete block, yet precise enough to gently tear toilet paper. Tom Johnson, our test technician in charge of this experiment, rigged it up with foam block to mimic the distributed pressure of the human hand, then configured it for a 100-pound load cell.

We used the Instron to determine the minimum amount of pressure required to flatten the LG G Flex, which turned out to be 30 pounds. We set the Instron to flex the G Flex at 30 pounds 1,000 times to see how it would hold up to repeated light presses. After 1,000 cycles, the phone worked just fine. So we upped the pressure to LG's claimed 88 pounds and compressed it 10 times (still working) then 990 more. The phone worked like new—just like LG had claimed.

So the LG G Flex can flex as well as the company says, but we naturally started wondering how much pressure this smart phone can take. We bumped up our test to 10 repetitions at the maximum capability of our 100-pound load cell. No problem for the G Flex. So we broke out our highest-capacity load cell and tried another 10 reps at 150 pounds, then 200, then 250. Still no problem. We increased the pressure by 50-pound increments, each time assuming the next 50 pounds would surpass the LG G Flex’s limits. At 450 pounds, we heard a crack. Everybody in our lab cringed, assuming the phone had finally broken, but it was just the case popping open a bit.

The phone still worked fine, and we were able to snap it back together by hand, so we kept going—500 pounds, 550, 600, 650, and so on (we even intermittently measured the arc of the G Flex to see whether all the pressure and repetitions were making it flatter, but found no significant difference pretest and post test). Flabbergasted, Tom finally set the Instron to the maximum pressure our load cell could handle: 1,000 pounds. When the G Flex came out fully functional, we all shrugged our shoulders—we had nothing more to throw at this phone short of running it over with a Mack truck or sitting a full-grown elephant on it. That would have been fun, but hardly scientific.

So we called it. The G Flex is not only an astonishingly resilient phone, but it also surpassed LG’s own claims by more than 1,000 percent.

—Glenn Derene